Steemit is always the busiest DApp:
https://www.stateofthedapps.com/dapps/steemit
So... from my rather limited experience, I would agree that Steem is undervalued.
On the ad revenue ...
I've been collecting BAT for a few months now. I know it's ETH, but it would be nice to be able to exchange that for STEEM... through some sort of tip jar.
Information of BAT:
Sounds about right at the moment... hoping there will be some method with less friction later on in the development process of BAT. Since all incoming BAT payments to a publisher are from browser addresses, it should be possible for some service like Steemit to ask users if they wish to identity their browser using the "Rewards" crypto address. Then any incoming monthly payments could be converted by the platform rather than the user...
However, I'm relatively new to the inner workings of how to interconnect everything.