Try not to argue “we’re doing this possibly weird thing here, then why can’t we introduce this possibly weird thing here also”.
I am firmly in the “sidewalks should ideally not be recorded as a separate way, and if they are in a few exceptional cases, should be nameless” camp. But that’s because I’ve grown up with maps that way.
I can see how in theory one should have one huge area for various kinds of traffic and then some limits about which traffic goes where. I just don’t think it is practical for OSM. It sounds like a total editing nightmare to me.