Ehh, the dip buying is a bit more of a PR move in my opinion. He "only" bought 150 BTC, which is more or less $6.8 million. Whereas while El Salvador is definitely not a powerhouse country levels of wealthy, I don't think that $6.8 million will make a significant dent on their balance sheet.
If this $6.8 million purchase is the only transaction they are going to perform in the entire year, then it may be an insignificant amount. But that is not the case. If I am not wrong, the government has already made purchases 3-4 times during the last 2 weeks. And doing by this rate, the combined worth may easily be in hundreds of millions of USD by the end of this year. And for an impoverished country like El Salvador, these amounts can be quite considerable. From what I heard, their gold reserves amount to just $3 billion.