Even a child can understand that avoiding infection is preferable to becoming infected.
No one wants to unknowingly infect people who are vulnerable, or elderly, or have just had chemotherapy, or have autoimmune disease, or are one of the roughly 100 people in New Zealand who cannot be vaccinated due to medical reasons.
We protect all of these groups, as well as the health of our overall healthcare system (which is falling over in most places due to Omicron numbers), by wearing masks indoors around others and by getting vaccinated.
These infections are manageable, but only with widespread mask use and vaccination.