Well, for one thing it scales more efficiently. If you watch 50 creators, giving Google a 45% cut is more efficient than paying processing fees on $20 split 50 ways. If you want to be truly fair, the logistics become basically impossible without massively increasing your budget. That's why, when most people opt to give directly, they're effectively choosing to reward only their most favorite channels while giving nothing to everyone else.
I don't necessarily think there's anything wrong with that, but it's not objectively superior to Premium, which does fairly distribute the creator's cut. Google is able to endlessly split your $11 creator's cut into micro-contributions based on exact watch-time in a way that individuals cannot replicate. Every creator you watch gets their share. Not as much as a direct donation, true, but nobody gets left out and it's considerably more than they'd get from an ad-watching viewer.