I doubt very much that printing money "always" works. There are problems with it actually, apart from the fact that the inflation it leads to is itself a "hidden tax".
Forcing people to pay tax in country currency also forces people to be solvent in said currency. If they no longer have to be solvent in this currency they are much more likely to...abandon it to some extent. For example they may increasingly use some cryptocurrency where money printing is out of the question. In addition to this, relying only on money printing..will put a strain on the currency (inflation), and they will abandon it to an even higher degree.