After checking the whitepaper, I am not convinced it is worth it...
First, in each round of block generation, 20 out of 21 witnesses are selected by DPOS like in Bitshares, and only 1 is selected by POW. So that does not leave much for miners.
Second, the block reward is now 0.0476 STEEM (after block #864,000, down from 1 STEEM previously, which was like DPOS witnesses). That's currently 0.02 USD.
I am not sure how long it takes to find a block, but it looks like this ship has sailed.