• Brendan Eich: Javascript and Mozilla. (that was enough for me)
• More and more people block ads(or annoyed by them)
• Why wouldn't people want free money for browsing?
• Google Inc. make mistakes frequently. Involving politics wasn't a good decision and many people will turn away and seek for an alternative. Especially how they do it... On the top of that, they seem to attack big YouTube channels who aren't left-leaning. Also, Google Adsense, in general, is way worse then it was a few years ago.

My only doubt was about the fact that people can abuse Brave's system and try to get insane amounts of BAT but no. They thought about that too and have a solution.