It will surely help significantly preventing a tactical nuclear strike from russia, though it won’t end the war. It is an absolute last resort trigger. Ukraine will be annihilated after they use it (Russia has way more nuklear weapons).

So somewhat good for them and OK to do so, though no solution and no substitution for western military aid.

A few months ago a german activist (I think it was Arne Semsrot) wrote a book about how low and middle positions in government agencies can work against the governments intentions in case of a extreme right wing takeover by the AFD. Though I don’t know, if it was translated to english or would be 1 to 1 applicable to the USA.

Though having cash is not enough. The stores also need to be able to accept cash without internet usage. I think we had a case in germany a few years ago, where some supermarkets could not sell anything, because the servers, to which the local payment system connected (also uses for cash) didn’t work. Not sure, if that was because of a security incident.