> You also get treated differently if things go wrong.

Not treated differently. Treated the same.

You are required by law to enter your country of citizenship using that country's passport (this is true for every country). Not doing so can result in fines or jail time. This is precisely to stop idiots from playing the "foreigner" card to try to, for example get out of paying a speeding ticket or parking fines.

You are spreading false information. I routinely enter my other country with a combination of US passport and national ID card. I haven't renewed my passport for that country in almost 20 years, more than half of which I was living there for.