While my kids were, well, kids I was bringing dozens of these back from Europe every trip, enough for them to share with friends and classmates at school. The chocolate they’re made of (milk on the outside of the shell and white chocolate on the inside) is typically European, i.e. richer than anything made here, and the little toys were complex, clever, and always worked. Never tried to bring them over from Canada but never had trouble getting them through customs in any of the three or four airports I’d fly through coming back from Europe. Always declared the value and showed “chocolates” on my landing card. Customs officers along the north border, both sides, seem to have peculiarly rugged sticks up their a$$e$.
I agree with your assessment that customs officials on both sides of the border seem fairly unfriendly. Ours seem to be worse. The last CBSA encounter I had was pretty funny. He asked me if I was bringing anything I didn’t plan to take back. I told him a gallon of milk and a five gallon can of gas that I was giving as a gag gift. He laughed and waved me on.