There are native mice all over the place. Yes, some are introduced/invasive, but there are also plenty of native ones too. If you live in the Americas, here’s the subfamilies they make up:
https://en.m.wikipedia.org/wiki/New_World_rats_and_mice
Mice serve as food for animals like owls, hawks, falcons, snakes, skunks, etc. Cats killing these animals’ prey makes it harder for them to find food.
I remember wanting to be a forum mod when I was like 15 and thought that it would make me cool on the forum. As a grown adult… no way. I am so busy between work, grad school, and my personal life, I have no time for such silliness. I have a lot of respect for mods that donate their own time to run communities.