I wear a seatbelt because common sense tells me I’m safer being restrained inside my car in an accident, rather than being flung 200 feet to certain death.
Wearing a mask will have no practical effect on containing the spread of the virus.
Nor will it have any positive effect on preventing me from being infected.
As I said above, there is an entirely different reason governments are mandating this. They know it won’t directly impact containment.