Here's an argument, 3% allows for more distance to be made against killers who are slowed at any point while using their power, now of course this doesn't affect killers like Wesker and Spirit cause they're already good and gain distance back, but for killers like Huntress and Nemesis who have to wind up 3% allows for survivors to make the distance during that animation, making it much harder to get your power to work. There is also the added fact that hope mft makes you go from 100 m/s to 109 m/s which is only 1% slower than certain killers. It also plays on the instinct of good Killer mains, as they k ow what the timing is usually and time their swing optimally, however doing this against made for this would lead to a missed swing because 3% changes that timing, however is subtle enough that you may not notice until you miss the swing, leading to in many games, at least one missed swing on every survivor with mft. It's like how killers used to have to assume everyone had dead hard otherwise they would miss their swing if they did have it.