Friends don't let friends use Brave.
Yes, it defaults to enabling their advertising features, but that's just it, a default setting, it isn't hard to disable if you don't want to "take part of the experiment".
It does not, you have to opt in.
You are right in the rest of your comment thought. And in general, when you compare default configs, Brave does far more to protect your privacy than Firefox does.
You’ll get notification badges on the Brave Rewards URL bar icon, but it isn’t active until you click on it and go through the BAT onboarding.
Well maybe due to the multiples bad things that brave did in the past.
Brave failed to tell the user that the people they donated BAT to won't receive the money if they didn't sign up to Brave Creators [1]:
> In December 2018, British YouTube content creator Tom Scott said that he had not received any donations collected on his behalf by Brave.[42][43] Two days after the complaint, Brave issued an update to "clearly indicate which publishers and creators have not yet joined Brave Rewards so users can better control how they donate and tip"[44] and in January 2020 another update to change the behaviour of unclaimed tips.
Brave (by accident? or so the company said) automatically added referral codes to cryptocurrency site URLs in the address bar [1]:
> On 6 June 2020, a Twitter user pointed out that Brave inserts affiliate referral codes when users navigate to Binance.[47][48] Further research revealed that Brave also redirected the URLs of other cryptocurrency exchange websites.
Eich bad
Incidentally, that was also the event that seemed to start Firefox's long decay.