It really isn't though. I also started using Firefox recently and I miss tab groups on mobile as well as on my PC. Yes, there is the simple tab groups add-on, but it just doesn't compare.
Brave is also easier to set up ad-blocking, because it comes with ad-block enabled and script-blocking two clicks away.

Don't get me wrong, I will continue to use FF, but Brave has some features, FF does not have (yet).