Very valid points.
To take it one step further, the opportunity right now is from mining the Tribes. They all are built upon the same Proof of Brain platform. This means getting the attention of the whales in the tribe. These people are, for the most part, different from those who are STEEM whales.
This is the great thing about Steem, we see the process continually repeating itself. The opportunities keep popping up with each new tribe.
Yes! You're absolutely right. It adds extra layers on top of mining STEEM. Now we can mine STEEM and use the same proverbial pickaxe (in the form of content) to mine other tokens simultaneously. This gave me the idea for another post ;)