Until the time of investment approval, bitcoin may be considered illegal in the country and it has been probably prohibited by the government of the country. The approval is therefore to let people know that they can deal freely in bitcoin and it may come with some guidelines, rules and regulations.
Exactly, bitcoin cannot be used in some other countries because of that, before a country takes in some business especially when it comes to currency, the first thing that they will do is study and put some regulations from it, approval is the word for successful usage of the said currency.
I think it will took so long if that happens as what you have said approval for the successful usage of currency in bitcoin besides other countries don`t consider bitcoin its because it is illegal and prohibited by the government laws also.