I have both (well Can/Pol)

I would say, worth the effort for sure.

I have used the Polish one when traveling thru South America to save major $$$ on visas, as well as in Turkey, and a few years ago in places like Albania, Romania, Bulgaria and Ukraine when Canadians still needed a visa. I often use it in the EU if the line is smaller. I will probably use it again next year when I go to Iran, just to avoid US customs idiocy on the return

There was a dumb rule until 5 years ago that you had to enter Poland on your Polish passport, so I had to do that in my teens/early 20s - never had any military issues, noone ever blinked an eye.

I am in the process of getting an ID card (dowod), and registering an address.