That the US is not one big monolithic entity is, I think, one of the most commonly overlooked things by many Europeans.
The silliness of some states' PE certifications is one reasons I never bothered taking the PE exam here. At the time, not sure if still true, but the exam would be 50% on whatever your engineering specialization was, and 50% combination of all other engineering disciplines. Why in the world would someone wanting to practice as a professional electrical engineer need to demonstrate any competency in civil engineering, I'll never know. That combined with the fact that in the first year of my first post-graduate job, I did maybe 2 months of electrical engineering, and by the time I was in a position to prepare for and take the exam, I wasn't actually doing ANY electrical engineering made it pretty much pointless. With the path my career took, being able to add PE after my name wouldn't have benefited me too much. In this state, that's the only restriction - I can have a job title with 'engineer' in it - in fact my company calls me a "senior systems engineer" even right on the tax forms submitted to federal, state, and local agencies. But I can not call myself "john Smith, PE" without having passed the exam and being licensed by the state. There was a time when they tried to say you couldn't use "engineer" at all unless you were a registered PE, but at some point that changed. Maybe all the locomotive engineers complained.