Someday they will allow bitcoin as a mode of payment because of its value and security. It is more comfortable than having an actual money you just need the address and thats it. I also use bitcoin when I do tasks and receive payments from different person.
bitcoin is basically created for that purpose. But actually in current time the bitcoin users are not present everywhere and even in modern countries still majority of people do not know about bitcoin, therefore we currently cannot use bitcoin as fiat currency and mostly use it for investment and trading purposes, but hopefully in future we will become able to use bitcoin for shopping and for so many other purposes.