When the kids were really little, one of us would take PTO for part of the day. Most sick and snow days still meant naps etc. so you could still work part of the day.
Once they got older, it's not a problem just to WFH as others have mentioned. I think each kid is probably home sick maybe once or twice a year? Not often. And they usually just rest, watch some TV, read. And for snow days, they play with neighborhood friends, read, make their own snacks etc. so it's not different from a regular WFH day. No need to take PTO unless I'm taking hours off to go sledding with them
