[decentralised]

Not all transactions require the smart-contract to know about the off-chain world!

The "oracle problem" is what I think you are referring to but I have a strong view that the problem of low quality data can be solved with existing mechanisms and tools.

My favourite method to dealing with information quality is by providing incentives to good quality sources and having a method that allows a third-party (anyone with an account...) to submit a fraud proof.