The IMF and World Bank can be a real pain in the a** for small countries. Bukele and his administration have made a bold move in legalizing Bitcoin and it's had positive effects on the country's development. As for the next leader, who knows what will happen. But, at least the foundation has been laid and it's up to the next guy to build on it or not. And you're right, let's call it what it is - Bitcoin. No need for all this "cryptocurrency" nonsense.
The next person will also continue what Bukele has done if the next leader has felt such a good impact on his country through Bitcoin. And the next leader will not forget Bitcoin just like that when he sees better developments in his country after adopting Bitcoin.
So I don't think this will change in the next leader because the people of El Salvador have also agreed to this. After all, the residents there can also be used by trading via Bitcoin to circulate their capital and make a profit and that can be an additional job for the residents there.