It's kinda weird, but then again Linda is one of the most adept shooters in the galaxy and has an excellent grasp of situational awareness. Whatever drawbacks this paint scheme takes from Linda's abilities as a sniper are offset tremendously by her natural tendencies to pick off a whatever from miles away with ease. As we can see from Argent Moon there's no need for her to have a solid colored or properly camouflaged weapon in that industrial setting anyways.

As much as I'd like to see her use some netting like Jun adorned over himself I can accept that some things in this universe exist as they are just to look cool and unique. Do I want to see a UNSC heavy cruiser painted in purple? Of course not because that really doesn't make sense. With an individual soldier you can chalk a lot of that up to personal style or whatever.