I think that volunteer snow removal is a good idea for several reasons.
1) Some folks are unable to scoop their own walks. Perhaps they are ill, infirm, elderly, whatever. I used to scoop my own walks (I lived on a corner) as well as the walks of some neighbors whom I knew could not scoop their own walks. My neighbor Joe did the same thing.

2) Some folks just don't scoop their walks even though they should. I scooped some of those, too.

3) Snow on sidewalks often gets tramped down and becomes icy. To keep this from happening, folks might need to wake up early to scoop walks. When I lived near Wesley United Methodist Church, I suggested that those of us who lived nearby could volunteer to scoop the sidewalks early in the morning before the hooves of students compacted the snow to form ice.
Ideally landowners should scoop their walks, but not every landowner is ideal.