Yeah I don't get the impression that you know too well what you are talking about if you don't know the difference between the EU and the Eurozone. Even if the euro were to break up/be abolished and resolve back to smaller currencies there would be a conversion key. The chance that the renmenbi, GBP, yen or even the dollar will have major issues look a lot more likely in the current climate - the renmenbi is still struggling to become a global currency and everyone can see the political struggles on the horizon, the GBP will continue it's free fall after the disastrous Brexit and the following depression, the dollar is widely overdue for a correction and will lose out if eg China starts dumping their reserves, not to speak of the endless debt spiral the us is in - similarly for the yen, with the high debt it looks unlikely to be a stable currency in the long term (even if it's mostly local debt). That doesn't leave too many options - with the euro a fairly stable option as long as people remember the nightmares of Europe pre-euro (and most outside the anglophone bubble do): huge costs and price uncertainty in cross border trade, big financial players gambling and manipulating against smaller currencies (as you still see in Africa today), and overall little trust in the local currencies.
Trust in the euro (not necessarily the EU as a whole, as it is a target for much local political hate & lies when it's easier to blame Brussels than accept responsibility for mistakes) is at an all-time high, with not even Italians wanting to give it up. No one wants the lira or drachma back.