Joining the Euro isn’t optional, its a requirement of joining the EU. The UK and Denmark have a formal opt-out.
Poles are fickle voters, their can be 20% swings in polls in the course of a week. They will not vote in the anti-EU/anti-Euro party, however. Voting for PiS is to vote for a lunatic, but his party takes up 25% of the vote.
PiS is so mistrusted by 75% of the electorate that they won’t ever get back in power in a coalition and the anti-EU vote is powerless.
The Finance Minister http://en.wikipedia.org/wiki/Jan_Vincent-Rostowski has explicitly said the Poland will not join the Euro until it become a viable and fit-for-purpose currency.
So the probability is that Poland will join the Euro when it is fixed., which looks to be a few years hence.
Poland’s overriding need is to become part of the EU and not part of the Russian Empire (again).
We don’t always agree on subjects, but in this case it’s good to read your analysis. Few of us here would have a clue about Polish politics, so it’s good to have a bit of informed commentary.