If this is a totally separate p2pool like network but miners connect to Bitmain's servers only to mine on it, then they get the worst of all worlds: They get the increased work loss of frequent restarts, they get the high diff shares that will prevent them getting paid consistently unless they have very large hashrates, and there is no actual decentralisation since they'll be mining at a centralised pool created by bitmain that just happens to use the p2pool code for its backend but isn't really p2peer.

If all of the above is true, then bitmain has tried to cash in on the decentralisation concept by paying homage to the idea using p2pool without actually understanding it.

Fail.