For my own understanding, it will be a little difficult because, every government has their own official currency, despite the popularity of crypto currencies,no government will like to loss her own currency to foreign one, and this has been the underground war going on with some country, that's while some country are still struggling to accept coin.

Forget that.
Money is one of most important tool to govern a country. Every national State is very cautious about everything could mine his ability to disposeof that money at his will. Think how long it took to get to a monetary union like the Euro: it was an unprecedented process, even more thinking about it was a peaceful one.
So basically everywhere in the civilised world you  are obliged to accept national currency from someone paying  your debt, and you must use such a currency to pay your debt towards the State.
Of course that means the State has the big advantage of regulate the value of the money (I.e. inflation) to adjust the weight of his own debt).
So why on hell would the State lose this incredible power?
Put it on another way: what’s the poin of paying your debt in Bitcoin? Are you sure you don’t want instead to spend the bad money (FIAT currency) and keep the good one(Bitcoin)?

Giving legal tender to bitcoin  would literally be the last thing a government would do.

Giving legal tender to a centrally issued and centrally controlled crypto-money... well, what’s the point? EUR and USD are good enough for this.

There are some countries that don't have their own national currency, and are in fact using someone else's. Panama, Ecuador and Zimbawe use the USD. In those countries they have already lost any control, in fact its worse because they are tied to the whims of the actual controller. At least with a crypto like bitcoin, no one is. The other temptation is to issue their own. which of course could be abused to no end like a traditional fiat.

So yes, they should accept it. They could have dual fiat/and crypto for a transitional period; but that also means abandoning the school of chicago or other economy schools that stimulate debt and inflation. And that is probably the biggest obstacle.

At present I don't think that might be done at a widely accepted level. Maybe in the future everything will be different. This will be an interesting change to accept, but they must have a very good reason to do it.

Until now I don't think the government is ready to accept crypto into their major industry, there are a lot of considerations that need to review before accepting crypto, crypto got the potential to make the economic become better but it also can be dangerous to the economic, so the government really need to think and do a lot of research before adopting crypto

i don't know whether they "should" do it or not but it is something that is going to happen anyways. bitcoin is being adopted and that is a growing matter. sooner or later it will be considered an alternative form of payment in a lot of countries and most part of the world will see it that way. you can already see the multiple countries that have accepted bitcoin as a currency such as Japan.
i guess another way of asking this question is whether a country wants to do the opposite of what the rest of the world does or not?

Accepting a crypto that wouldn't control?
Forget it.
It would be easier (for a country) to issue an own controlled crypto, as Venezuela did with Pedro.
Do not forget, that National Banks (who issue currency) are private institutions.
Do you get the point ? 

To accept Bitcoin and other cryptocurrencies on a governmental level would give some other dimension to them. That would mean they are formaly recgonized and regulated and thus introduced into economy system. That would give people more confidence and security to deal with cryptocurrencies. Still in practice that will not be so easy to performe and every government has its own attitude towards Bitcoin.
Some see only bad sides of government recognition, like taxation, but this you have now already because Bitcoin transactions are taxed in majority of countries. But we mustn't forget that formal adoption would bring many good sides and further progress for all cryptocurrencies and some obligations should be accepted, that is inevitable.

as many countries are accepting crypto as payment for tax and donations - I guess governments will accept in time.