Yep, and most importantly, the gas from those smartcontracty things help keep more miners online defending the Bitcoin network, instead of lining the pockets of people that lobby against bitcoin POW. All without any forks changing the basechain.

timechain

bitcoin

Some info on Rootstock.

I think Sergio has shown himself, over many years, to be a bitcoin maximalist that just wants to do more smart-contracty things with his bitcoins. I have no use for the things I've seen from RSK, but I wish him the best of luck in pulling the mETH folks over to bitcoin as they lose faith in the monetary integrity of their token.