Does a cellphone photo of your passport id page and visa suffice as a copy or is a hard copy
required?

I suppose one could ask at the local psb.


For banking matters I do believe the physical passport is required and other
things such as air travel...not sure if train ticket agent hsr would accept
Cell phone photo. Of course hotel needs original. Have been checked for
passport when entering by car cities with events...ie Beijing Olympics, Shanghai
Expo. Not sure if cell phone photo would work.

Is the risk of losing your passport while traveling in China worth keeping it in
a hotel safe when available?

In general I would answer, no.