Yes, RSK has been working for a few months now. It isn't as popular as the Lightning Network (different use case) and didn't get as much attention. Since it's an off-chain solution, it didn't require a hard-fork to start working. Don't expect people to abandon Waves or Ethereum instantly. Hardly anyone knows and mentions RSK and it will take some time before more people understand how to use it. Miners might quickly become interested in it because of merged-mining. It should not affect BTC mining performance and can result in additional profit.