^^

It puts more stress on your drives. Say a 128kb file gets written to your array, 16kb gets placed on each of your drives and each drive has to erase a block to make this write. Total writes done = 8 times the block size. If stripe is 128kb or more in the same scenario then your total writes are 1 block size or 8 times less.

It wouldn't make wear leveling less effective, but it would increase writes quite a lot and you know the consequences of that yourself.