How is registration going to help against bots? It's an honest question, maybe I missed something

I mean, it's one thing when user has to register on each faucet. Then it doesn't make sense for bots to waste time and money creating accounts on that single faucets. But with registration on FaucetHub.io that'll change. Assuming 1000 faucets will move to FaucetHub.io, creating 10 accounts allows abusers to make 10000 claims with their bots. It doesn't help in any way. And I'm completely skipping the part where a bot for creating accounts is created, which should also be easy.
It helps with monitoring malicious user(s), flagging, reversing transactions, alerting entire network about a malicious user and a lot of other things
But the malicious "user" will probably be creating new accounts all the time. And all the other things you mentioned doesn't really change whether you require registration or not. You just changed the user identifier used in these action from cryptocurrency address to email address.
That's still a method of prevention. I use a combination of tools I've written with registrations and it works like a charm on my websites.
Anyway, I don't know why there's this talk going about. I just want to launch my own microwallet lmao.
I'm not forcing anyone join faucethub. If they don't like what the site will offer, they can freely join any other service

Anyway, sticking to my ideas/development.
epay for the win!
From what I understood, you won't have to register for each faucet with FaucetHub.io, only one registration for entire FaucetHub.io will be enough

Correct.