It would certainly make sense from a marketing perspective to claim it's using tor, and then have a tor-proxy service (think onion.cab) use tor for hidden services and also attempt to use tor for clearnet traffic but fail back to regular proxy if it fails.

If it were directly using tor then I'd have to agree that most people wouldn't use it. Only those that are technical enough to understand what's going on and the security aspects. But they wouldn't be using Brave for the Tor functionality, they'd be using Tor Browser.