I work at Google on its Ad Exchange, literally the exact product BAT is trying to replace (with Brave trying to replace Chrome). I will say three things without divulging anything:
The complexity of our software and business teams is very high, BAT has a long way to go. Every majorwwebsite uses us. Including the one are on right now. Open the network tab and type google or pubads.. ;). Then go to any other website and do the same. The browser is the easiest (and least profitable piece). Running a full ad ecosystem from sell to buy side (pub to advertiser) is no joke and most companies fail or are failing. Lookup the ticker symbol RUBI...
As alluded to this is not a project that requires a blockchain. We operate completely in FIAT and have no sticking points around it.
Google already has a product that does the exact same thing (https://contributor.google.com/v/beta) and publishers don't even care that much. Fact is people already tune out ads and they are quickly becoming less annoying.
BAT may go up in value because of blockchain hype and overvaluation. Hell it may even have a niche I think the brave browser user numbers are interesting... I would not recommend investing in the token and I am a blockchain enthusiast.
(likely deleting this post soon)