I had to do it years before Covid while caring for a cancer patient. A man at my church who cares for his wife with MS who takes medication that lowers her immune function did, too. You never know why the mask. Some with severe allergies wear them when the pollen is high.
Still, there is no evidence mask wearing helps in those situations.
I wore a well-fitted N95 the other day, I was mixing concrete for some deck footings — the masks work well for that.
I have pollen allergies. May be I should start wearing it during months when pollen count is high.
Bless you