Hi. Yes although in theory a data consumer could hopefully obtain the street name for a sidewalk from the nearest highway, so far they have not done so.  As a result there is a movement to add `name=*` to sidewalks.  `street:name=*` is an alternative to this emerging practice that is more semantically accurate.  The name applies to the whole street, not just the sidewalk.

https://wiki.openstreetmap.org/wiki/Key:street:name

Several recent forum topics: https://community.openstreetmap.org/t/should-sidewalks-and-crossings-be-unnamed/136661
https://community.openstreetmap.org/t/what-problem-is-this-named-sidewalk-creating/136889

