Nope. It’s something they are making progress toward but isn’t available fully. You can read more about that over at PSA: Current and upcoming changes to Rewards and Creators
No. The browser is focused on you not seeing ads and to limit the abilities for advertisers and others to track your activity across the internet. Signing up for an account or abiding by government regulations for things like banking wouldn’t be a violation of anything that the browser is meant to do.
Who said you can’t use it? Brave Wallet is what you would use to send or receive any cryptocurrency. You can buy, send, or receive crypto from most things. What you’re speaking of here is just that you want to earn BAT from viewing privacy preserving ads and have it sent to your Wallet, but that’s not available for everyone yet. If you want to earn and receive BAT, you will have to link to Uphold. Otherwise you just have to wait for on chain Rewards to be available to you.
Oh, and I have a FAQ pinned to the front of this website. If you had taken the time to look through it, you might have also seen things like below which would answer some of your questions/concerns.