That’s kinda what we heard about Lightning and payments, but we can currently see that there’s more BTC on Ethereum, than there is BTC on Lightning according to http://btconethereum.com.

I doubt there’ll be any significant value locked in RSK/Sovyrn, when most of the liquidity is on Ethereum. Plus, it’ll take time for BTC developers to learn Solidity, and most of the DeFi network effect will be on Ethereum and other EVM compatible chains.