Ok, I glossed over color matching the wall patch. Fair.

But there really aren’t many walls you need to open in a house. There is probably 2-3 wet walls, so unless you need to retrofit some ducting why are you opening a wall? Code says there are no hidden wire junctions, so you’ve just got continuous runs of romex that are secured before they terminate… what do you open a wall for?

Most of the drywall repair is just physical damage to the drywall itself.

In theory, I'd rather get at something through an access panel than via cutting and patching drywall, but practically speaking, you're right: it's rare to have to open a wall, and an access panel that isn't specifically for something you need to access regularly is just a nice-to-have, and not even necessarily all that useful unless it provides the access you actually need at the time.