Reserve currency it is for that and RESERVE-to use it as a reserve, savings for a crisis and other bad situations.
You are suggesting that we take one of the most unstable financial instruments in the world and persuade the whole world to start using it as a reserve currency.
I though of this long time ago, if we are going to bring back our fiat to be backed by an asset, a commodity then we can start using bitcoin but the problem is its volatility coz the government can't just buy all the bitcoin in the market. I'm out of words to describe but it would look like we are not giving Satoshi's work an honor since he wasn't made it for that purpose. Aside from that, gold is still better than bitcoin when we are talking reserves.
Are you sure that this is a good idea?
No, not really a cool idea but who knows that it could someday?