Turing-complete language is just the base layer. You could build more limited languages (decidable languages) on top, which are more appropriate for smart contracts.

There is a new decidable language that compiles to EVM bytecode: https://github.com/ethereum/viper Visually it looks similar to Python. The language is not turing complete, and one of the advantages of this is it's easier write bug free code and easier to verify that the code is doing what you think it's doing.

The reason why the entire EVM is turing complete (and not more limited) is because making it decidable instead is harder than making it Turing complete and would have made the protocol more complex: https://github.com/ethereum/wiki/wiki/White-Paper#computatio...

A Turing-complete language is base layer: you can build any paradigm you want on top.