No obvious benefit to the miner, just a short lived disruption of the network (I don't think it is big enough to qualify for a DoS). If successful, it would split miner resources and cause the next block to be mined at half speed.

The main point here is that relying on node current time is dangerous for consensus. Even if it doesn't cause major trouble, it complicates things. Fortunately the 2h rule is the only place in bitcoin protocol that instructs node to make a decision based on its own clock.