Would chips let you by if someone did happen to have snow tires and no chains?
I guess probably not if you are carrying chains in addition to the bizzacks.
To be honest I see some snow tires on cars of people who live up in Tahoe, but for those who only drive in snow once or twice a year, hard to justify a second set of wheels and tires, and the room they take up to store them.
4WD fitted with ATs are not required to wear the chains, but other than that, when the CHP says to wear them, it is mandatory.