Biggest problem with tourist destination cities in Europe is that they are old... definitely not ADA friendly. There are cobblestones everywhere, steps everywhere, and curbs the size of nebraska with no ramps. I suspect in many places the scooter would be more hassle lugging up and down stairs/curbs and avoiding cobblestones... than it is worth.

Just got back from northern Italy and Germany this summer with my family. I'm a one-bag traveler who uses a 26L backpack. They all insisted on taking roller suitcases. It was a constant nightmare of schlepping the heavy suitcases up and down stairs & curbs, and horrible to drag down many streets.