> other node installers didn't actually install node (just add repos/ppa/etc)
That's a good thing. Ideally you don't even want an "installer" (if by installer you mean a shell script) to add a repo. You just want a gpg key blob/id and a repo URL; OR a "release" package for you distro, which contains the above and will install them in the correct locations.
This means you get regular updates via eg apt-get upgrade, you can see exactly what files a package installed (or even will install if you download the package file first)
Installing software from a shell script like that is a terrible solution quite frankly. `curl|sudo bash` type things are the marquee tag of the ops world.