Smart contracts are primarily for the financial system. And the financial system is just starting to create crypto currency denominated financial instruments. JP Morgan issued a 7 day Ethereum denominated bond on the Ethereum blockchain last week.
The challenges Ethereum has are it’s currently too damn expensive to pay miners fees (called gas) to run smart contracts and the blockchain is bloating really fast. So If the current price rise continues, Ethereum will restricted to high value financial instruments, pushing Ma and Pa onto Qtum or Eos or whatever.
Here is one contender for a Bitcoin smart contract language, I don’t really know anything about it:
http://www.rsk.co More info here:
https://www.coindesk.com/opening-testnet-to-public-rsk-announces-3-5m-funding/I haven’t dug into the detail but isn’t Tether just a smart contract on Bitcoin?