I wear my roshes, haven't even worn my margielas unless I'm walking around the corner.
I've worn things on a margom serena sole all over Europe. GATs will do as well. It really just depends on the shape of your feel and whether or not you like your shoes more snug (Margiela) or loose (Commo Projects/Buttero). Europeans, particularly in cities like Paris or London, where driving is a huge PITA. walk everywhere as well, and they seem to do fine, even in leather shoes. Yes, if you insist on visiting 6 churches and 12 stores a day, your feet are going to ache. But that's going to happen anyway.
When I travel, I limit myself to one or two activities a day, and meals. To me, it's madness to try to cram things in.