Furthermore, the value would remain high only as long as the bitcoins are not spent. If countries bought bitcoins every year, the price would certainly go up -- until they decided to spend them, and then it would fall by just as much.
this is true only if all country decide to spend them at the same time, the probability of this is very low, so while some might spend them the other will keep buying, mantaining the price at the same level at least, with small correction toward rising
If countries buy bitcoins that they can't spend, then they are effectively burning them in order to subsidize other bitcoin holders.
Don't forget that if the price goes up, then it also costs more to obtain them. That doesn't help poor people.
Anyway, in proposing that countries buy and hold bitcoins simply to increase the price, you are asking for people to subsidize you and other bitcoin holders. Is that what you really want? A subsidy?
The real value of Bitcoin is in its ability to improve the lives of the people that use it and not the people that hold it. If you are doing nothing but holding bitcoins and hoping for the value to rise so that you can cash out, then you are helping nobody.
1-this is true only if they don't buy before the price rise
2-i agree with this, but some holding is recommended besides what btc is for, one should also think about his economic condition, we can't spend every penny we get
3-well you are helpinh yourself, it's not like we are living to always help someone else, there must be a little healthy egoism