If a unified UI was of utmost importance, then they should have had a second disc that served as an install disc. That way you still have the data on a disc and can upload it to your Xbox from there instead of having to download it from an internet server, thus wasting more time and wasting bandwidth. Also, having an install disc ensures that you will always have the data on hand regardless of whatever happens to the XBO servers in the future. Even if your copy gets lost, destroyed, or rendered inoperable, other copies still exist out there and can theoretically be obtained, as opposed to digital content (full games, DLC, or updates) where once the servers hosting that data are shut down it cannot be retrieved again and is rendered permanently unavailable to the user. For the original 360 versions of Halo 3 and Halo 4, this will never be a problem as the multiplayer data is all on a disc.

These concerns are one reason why I'm skeptical of digital distribution and why I do not own an mp3 player or e-book reader and why I do not buy anything digital if I can buy it physically. Aside from Halo map packs, I've bought a tiny handful of digital games, with Galaga, TMNT: The Arcade Game, Perfect Dark HD, and Mega Man 9 & 10 being the only ones I can recall buying. I do have a digital copy of Pikmin 3 and a couple of indies on PS4, but those were all free promotions (got Pikmin with the Mario Kart 8 promo, and I got those PS4 indies free through PS+). There's no way in hell I'm ever paying $60 for a digital copy of a full game.

Sorry for the tangent, but the physical vs. digital issue is serious business, and having physical copies is that damn important to me. So I have to get up off my butt to swap out discs in the machine or drive to the store to buy a new title. Big whoop. Better than losing ownership and not having the guarantee of a lifetime of enjoyment.