N95 masks are used as part of a package of PPE. That includes eye shields, gloves, and gowns. There's a complex protocol to put them on, and to take them off.

Without the rest of the kit, and without careful adherence to correct donning and doffing, there are at best marginal benefits to mask wearing.

There's some concern that those marginal benefits are eliminated if people wearing masks go on to engage in risky behaviours. These behaviours include increased touching of their face (often without immediate handwashing afterwards), reductions in distance between people, increase in frequency of leaving the home, etc etc.