It is.
I do it anyway.

I really can't stand versus fights. There's something about fandom that makes certain people want to split up, put on armbands, and argue to the death over whether the Hulk can beat a Bolo. Outside of select cases, that doesn't interest me and hasn't interested me since before I was old enough to smoke. I just came down on the Super Star Destroyer's side because I'm familiar with those arguments, the two ships are comparable in that they both come from science fiction universes where levels of firepower and durability can be measured, and I distinctly remember the SSD being the tiger in the henhouse.

I do argue what fictional tech can and cannot do. Which is still pretty silly, but I'm not as silly about it as I used to be. Trust me, if I could reach back through time and slap some sense into myself circa 2006, I'd do it in a heartbeat. But fictional technology does what the author says it does, and it's a waste of time to argue otherwise.

There's people who say the UNSC are idiots because Reach was defended with orbital platforms powered by groundside generators, with the energy being transmitted through microwaves. If the UNSC has microwave lasers in the gigaton range needed to power an ODP, they may as well put those stations in orbit and fry the Covenant warships directly. And if the UNSC has a material that can absorb gigatons of energy and convert it into usable electricity, they ought to coat their warships in it and laugh off Covenant plasma torpedoes.

But fictional technology does what the author says. So, the proper in-fiction reason why the UNSC didn't do the above is "If it would work, they'd have done it. Since they didn't do it, it wouldn't have worked because of some 26th century technobabble problem." So, the exact opposite of this.

The reason I argue this stuff is because I'm an engineer. Not only do I disagree with the general population on what's cool and what's stupid, I know enough that common science fiction tropes look even more stupid.

Example: the Incredible Hulk was created by exposure to gamma radiation during H-bomb testing. Spider-Man was created when mild-mannered Peter Parker was bit by a radioactive spider. The Flash gained superspeed when a shelf full of chemicals spilled on him at the same time he was struck by lightning. Back when those icons debuted, radiation was this strange and scary thing. It was unknown. To the average joe, radiation might kill you or give you burns, but maybe it would also help you. Radiation tampers with genes, after all, and DNA is this great unknown with a ton of potential. And chemistry was turning out all this groundbreaking new stuff, plastics and herbicides and Tang.

Ask a scientist back then, and he would have told you that the only thing an H-bomb is going to turn out is the Incredible Hunk Of Tumors and Radiation Burns. Now it's common knowledge. Same thing with chemistry. The mechanics behind these origin stories are no longer plausible to the average reader, and they've been updated accordingly. Flash's speed has been thoroughly retconned so that he gains power from the Flash Force. Spider-Man and the Hulk have thus far resisted the change, but only in the comic books. The movies sought to reach new audiences, and their origins were updated to genetic engineering and genetic engineering plus radiation.

Nanotechnology and genetic engineering are in the same limelight that radiation and chemistry stood in fifty years ago, and I know just enough about nanotechnology that common fictional applications are either absurdly unimaginative or pure bullshit. I mean, look, when nanomachines can turn you into an exact duplicate of your late wife and change you back in the snap of a finger, that's just pure bullshit. It's magic, but the author expects you to nod and take you seriously.

Bonus points if you know exactly which story I'm talking about. The author is pretty famous, and it was one of his last works.

At the same time, I know enough about genetics to know that common fictional applications are either magic or bullshit. And, ah, I have zero problems with scientists extracting dino-DNA from fossilized mosquitoes and patching it together with amphibian DNA. I know all the technical problems with it, yes. I just don't care. I know that true velociraptors had feathers and were the size of a particularly large turkey. I don't give a shit. I love Jurassic Park too much to let logic get in the way. I can even watch the sequels and enjoy them even if I am put off by how stupid/immoral the protagonists are.

(By the way, that was a hint)

The thing is, writers are rarely engineers and engineers usually don't make good writers. They don't understand science. The technobabble is just something neat that enables the story to take place. If I'm entertained, I'm too busy enjoying myself to pick the science, gunplay, or tactics apart. If I'm not entertained, then nitpicking is what I do to entertain myself.

The answer to "Can a fictional technology do that" is "Yes, if the end result is sufficiently entertaining." If Cortana used magical never-mentioned-before nanotechnology to upgrade the Chief's suit into something that looked like a worthy successor to the Mark VI, I wouldn't complain much. But because the Chief's Halo 4 armor is visual vomit, I can only talk about how 343i got it wrong, wrong, wrong, and their technobabble was terribad. Same goes for the nu-Jackal and how Lasky's 'leadership' has reduced the UNSC Infinity to a punchline. "Oh, great, what patently obvious ambush did the Infinity wander into this time?" "Whatever happened to those escorts that the Infinity can carry into Slipspace? Are they too good to be sent on lowly scouting missions?"

So, returning to the original topic of what energy blades can and cannot do:

If the Halo Graphic novel was released today, the swordfight would merit only a single mention in the midst of "I enjoyed this, this, and thought this was pretty cool." Granted, I might harp on it a little more. I've found that my enjoyment of specific examples of Halo's fiction is tied to my enjoyment of the fiction at large. But I loved the Last Voyage of the Infinite Succor. Hunters in the Dark struggled to keep my attention.