We are also using the Bitcoin hashing power to merge mine RSK (rootstock), smart-contract sidechain similar to Ethereum based on the Bitcoin blockchain. We believe that sidechains have a high potential, therefore we decided to support this project.
However since the network rewards are very close to zero, we decided to not incorporate RSK to dashboard for the time being. It’s possible that the RSK rewards will increase noticeably in the future. In that case we’ll surely extend the RSK support and the miners will be rightly rewarded.