In all do respect I'm not comfortable with saying "if you don't have the illness you don't need one" N95 masks go a long way to preventing inhaling the respired droplets that can carry the virus. .
You are right. But if you don't wear the mask correctly, or if you take it off in an inappropriate manner, then all those droplets you try to avoid will still be in contact with you.
What I am saying is that most people blindly wear masks and feal safe when they are still at risk because they spread the surface of the mask on themselves.
If you have an appropriate seal and don't touch the surface of your mask when taking it off (it takes practice) and clean the mask and your hands correctly, it greatly improves your protection.
But I've seen people lower the mask on their chin to talk, then exposing the innards to unprotected skin, and then put it back over their mouth to inhale what's in the mask.
I also seen people put on and take off masks multiple times without cleaning them.
And I've seen people touching the mask with their hands and then putting the same hands inside the mask and on their skin, thus exposing both the mask and their skin to potential droplets that the mask was supposed to protect the wearer against.
So... Mileage will vary. The mask is not a magical solution.