not strictly true, Denmark (and the exUK) have official opt outs, the Swedes have an official policy of intentionally failing to meet the criteria for joining and the Poles and others are also dragging their feet
As I said, all
new member states have to adopt the euro eventually. The exceptions given to UK & Denmark don't apply to new joiners.
And Scotland can be sure that the they won't find favourable negotiation partners in Brussels if they say that it is their intention to deliberately skirt the rules and punt on the currency.