just recently Israel ban Bitcoin because it has been perceived to be a tool to finance their enemies,
This sounds more like propaganda against Bitcoin, specially since it is source-less...
For starters, Israel "enemies" aka people whose home Israelis are occupying aren't purchasing their weapons. They are manufacturing it domestically and mostly inside the prison known as Gaza. For example their rockets are made out of the ancient sewage pipelines that ran from Egypt into Palestine.
Additionally majority of their weapons are spoils of war. These are stuff Palestinians have taken from their enemies aka the occupiers. For example they now own at least 4 Merkava tank they seized recently.
Almost all the guns Palestinians have are also Israeli made, either acquired by taking it from their military bases or buying it from Israeli soldiers!
Why should someone as big as a government
Well in your story, Israel is not a "government". It is an illegitimated regime that is more of a terrorist organization than a government.
Big up to El Salvador who was bold enough and has a smart leader to have discovered the potential advantage of Bitcoin and adopted it accordingly,
Bitcoin's benefits are for individuals not for countries (on big scale). Of course the case of El Salvador is slightly different because we are talking about a very small country with a very small economy and lots of problems. So impact of Bitcoin there can be considerable specially if the plans their president has (tourism, foreign investor, etc.) works.