Yes affects the miner. when ETH fork, then there is 1 new coin from its fork. Whether the miner keeps mining the ETH from the assumption of Network hashrate diminishes due in part to miner switch mining to coins of ETH fork results. or also some people to move mining to new a coin with the assumption of his Network hashrate is still small.
Last year these types of forks were helpful at experimenting with new ideas and bringing in new people due to publicity. Maybe this fork will help everyone too.
My two pence.