For example I use Kaiser, which is basically "full stack" where they are both the insurance and health provider. The upside to that is that they are big on preventative care, since they are on the hook for the cost if you get sicker.
But their software still sucks, especially their billing software. I just lost my insurance for a week because of their billing mistake, and it took me a week to get it fixed (and it's still not settled but at least my insurance is active now).
So for example I'd be really happy if Kaiser had better billing software, and they probably would too because their costs would go down.