Brave is just an intermediary that replaces ads with other ads. It's an adnetwork delivered as a browser that creates ad inventory on top of the page instead of within it. That being said, the tokens are basically worthless. This is not what the digital advertising industry wants and Brave is not going to get any decent advertisers with this. They'll end up with the same shady affiliate/performance marketers running…
Besides that, Brave is a browser first, currency layer/ad network second. It doesn't need advertisers. It needs users. The more users it has, the more value there is for advertisers too.