Whether you don't wear them because you're already vaccinated or just don't want to, that's none of my business.
My question is this: Suppose you actually get COVID. Lets say you aren't asymptomatic but not deathly ill either just hacking cough, dulled senses the standard normal case and you test positive for COVID-19.
Would you wear a mask if you had to leave the house at that time? Whether grabbing groceries, going to doc's office or whatever reasons you had to leave the house with COVID?
Personally I can't be asked to wear a mask in general (vaccinated anyway) but I do have an N95 on hand. If I end up getting the thing and hacking my lungs out for a couple weeks then yea I'll wear it to be considerate when I can't avoid coming in contact with others.