some countries are now regulating bitcoin but i did not heard that they combine bitcoin to fiat.

 I think that will not really happen even if all countries will start to regulate bitcoin because fiats have thier own value and physical shape while bitcoin is only a digital currency that do not have a physical form. So overall that would be impossible to merge them both.


Merging fiat or local currency to another local currency is more realistic , same as when combining crypto to another crypto.