The odds are pretty interesting. Now Bukele has found out about this and seems to be hinting on social media. But do you genuinely believe El Salvador can magically get to a billion worth of bitcoin? They currently have over $700 Million. They would only need $300 million more. To me it seems a lot.
If they manage to reach $700 million, which is already a substantial amount, then they can also break into the $1 billion mark. They are motivated and do not consider the risks inherent in the cryptocurrency market.
$1 billion is a significant achievement; if they still have the funds, they will likely reach their goal and serve as an example to other countries that want Bitcoin to be part of their reserves. They can double the amount they stake if the market turns to their favour.