Main reason is that I can use my own sync server, I don’t trust Google nor Mozilla to store my passwords, bookmarks and history, etc. but I trust myself.
Second reason is that it’s the only non Webkit related browser left after IE, Opera gave up on their own rendering engine, so once Google decides to implement anti-features there is almost no way around it anymore. I like to think that if at least I use it, it will somehow stay relevant enough that the W3C can keep existing and Google needs at least engage in some kind of conversation about their anti-features instead of just implementing them and forcing it on everyone automatically.
Third, uBlock origin works very well, even on my Android mobile phone.