Look at it this way. By making it a grind fest they're preventing lesser motivated players like you from acquiring it, which means less people run around thinking they look badass when they really look like a ******* moron who flunked out of the suit class in sniper training!
...seriously, they look terrible, do people ACTUALLY think they make you look badass?
Not theory to boosting at all. I regularly see people who have played less than 200 games total running around with them. Which means assuming that they had the challenge from the start, they had to get enough points to buy a sniper rifle with a chrome barrel (Cheapest is USR at 6 points plus chrome barrel another 6 points). That means earning a minimum of 18,000 experience to just buy it if they buy nothing else. If we assume they are good players then maybe they could buy it all within five or six games. But did they really manage to get that many kills that quick? Admitedly quick scoping seems to be back (played against someone who was on 26 for 2 and was quickscoping around corners using the tactical lean) but there just seems to be too many out there and strangely it is very rare you see someone wearing a ghillie using a sniper rifle, it tends to be the Honey Badger or AK12 with silencer and grip (which seems to be more accurate and effective at range than a DMR). While I know that many people work hard to get the ghillie, as soon as I see one in game my first thought is hacker/booster.
Ghillie Suits look like someone went to poo in the forest and had issues putting his clothes back on.
To be honest I don't see the point of the Ghillie Suit at all beside esthetic; they don't make you less visible, unless you consider a couple maps with lot of bushes equal to three or four maps without a single bush; they make you look bigger (you literally have parts of the suit outside the borders of a Riotshield) and thus easier to spot in places without nature (ex.: Sovereign map) and it gives no other benefit that be hard to see by the naked eye in some parts of Prison Break and Overlord maps, that's mostly it. Beside that, in my opinion the Ghillie Suit looks horrible, rather use the Concealed Cobra.
I see this uniform as a "multiplayer Easter egg" tool more than a precious achieve or a good looking suit.
I pretty much exclusively snipe. There's only a couple matches that I don't find it worth the trouble of doing so. That being said I'm not where near completing the challenge yet I was seeing players with the Ghillie Suit day 1. Now there's at least 2 or 3 a match and I know non of them put the time or effort into using the attachment.
If you get 20 kills per match with sniper rifles, it takes 43 matches to complete the challenge.
Let's say your not a good sniper and you get around 10 kills as much; 85 matches then.
Question is: how many matches do you play within the two weeks you have to complete the challenge ? Not "Why do you need so many kills??" and etc.
Of course if you play a lot you will complete challenges without noticing it while if you play a few matches once in a while it will look like it will take forever.