By and large they aren't full apps, they're small shims, but ultimately this a decision that Google took when they started misusing the system designation for a

By and large they aren't full apps, they're small shims, but ultimately this a decision that Google took when they started misusing the system designation for apps to mean all of "should come back on hard reset" and "should have full admin permissions beyond userland" and "should be difficult to remove because you'll bork the OS services" at the same time.