I see guys climbing out of trucks wearing sweats at truck stops all the time. I assume they are mostly OTR folks who do little but drive, drop, and hook. Not me though, I deal with the public and am cognizant of the image I present to our customers when I deliver.
I own them and I wear a pair around the house. They are comfortable and warm. I have another pair which would be a stretch to call sweatpants but they are pants made by Nike that I wear to the gym for working out in.
I also used to have an old pair that I wore for painting and other projects around the house.
Overall, they are more comfortable and warmer than jeans.
But I don't wear them out in public just doing things. I have jeans for that.
I wear play clothes to play and street clothes in general public. I wear dress clothes when appropriate, and a suit when it is proper. The silliest thing I see is a flabby guy in shorts and tennis shoes and a hooded, insulated parka on cold days. Usually the parka is a college team logo. I didn't even dress like that in grade school. I guess I was born old.