Yes. Seatbelts will not prevent accidents, but may save your life in case you get into one. Just like the vaccine doesn't always prevent you contracting covid, but if that happens, it might keep you out of hospital.
While the masks do not totally prevent spreading or catching the virus, they will reduce it. Not wearing a mask or not taking the vaccine because they are not 100% efficient is like not wearing seatbelts because you still might die in an accident. Masks and vaccines also protect others, not just yourself. (No need to comment that vaccine does not totally prevent you spreading the virus. It makes you spread less virus.)