"Brave just reported 5.5 million monthly active users and 28,000 publishers participating in its attention token system, which strips websites of their ads and trackers, and runs non-intrusive, non-tracking adverts from Brave's own network in their place "
I haven't used Brave but surely there is quite a difference between having an ad blocker in the browser and replacing ads on a website with your own ads that you profit from? Even if Brave claim that the publisher can get up to 55% revenue from those swapped out ads, it still means that 45% is going to line the pockets of the Brave browser creators.
The deal gets worse as well if you read the T&C for the ad swap program they advise you only get paid out once the funds reach $100, which could take years to achieve since only Brave Browsers can participate in this and they have a very small user share. They also pay out in cryptocoins so what might be worth $100 in Etherium now might be worth $5 by the time you get your payout with the exchange rate on these crypto currencies.
It is like Samsung or Sony bring out a new TV that replaces the ads shown in the commercial breaks with their own ads and offer the TV stations 55% revenue in exchange.