Yeah, good point. Heavy snowfall can collapse even a 4 season tent. Still, even in a snow cave, one had better check the entrance and vent holes periodically. Buried alive ain't all that great and neither is suffocation.

The other problem with building shelters is yes time but also sweating. Building a snow cave can work up a good sweat. "You sweat, you die" is I believe an old eskimo saying.

HJ