Hi rphyrin,

Yes, absolutely there are circumstances where mapping sidewalks separately records very useful information, and other places where it adds no useful information, makes the map look crap and incomplete, and can actually complicate routing decisions. 
I would argue that this particular mapping does the latter. I have married separate sidewalks in scenarios like your example when the situation justifies it.
The mapping is wrong for a start, because footpaths end in the middle of nowhere and don't rejoin the highway even though there are pavements available to continue a journey. 
We don't have jaywalking rules in the UK, you can cross a road anywhere, but groups of people for whom specific crossings infrastructure is important are people in wheelchairs who need to know where drop kerbs are and people with visual impairment who may depend on tactile paving. I've already recorded these types of crossings in the area this contributor has added to, they have added more crossings but not even indicated whether they have accessibility features. 
It feels like someone helicoptering into an area, adding some incomplete data wrongly to a couple of blocks and then disappearing again, and it demotivates me from contributing further because who wants to contribute time and effort to a crap map? I might be more sympathetic if they could justify why they have added sidewalks to two or three blocks in random cities around the world?