In my opinion, a collapse is highly unlikely. But if it happens, you will have more problems than bunq not being around. For example, in the case of hyper inflation (could be called collapse?), your wages will be worth a lot less by the time you want to buy groceries with them, So what will you tell your boss? You want more? Where is he going to get it from? Same goes for bunq's employees. Will they keep working if their wages can't pay for their life anymore? Nobody will let this happen so the government will take all kinds of actions which will actually make everything very unpredictable. I guess if other currencies remain unaffected you could quickly buy those, but will they really stay unaffected when something as big as the euro looses stability? I wouldn't worry about it, even if it was likely, it's probably not something you can really prepare for.