It's still a Linux distro. Ext4 partitions, glibc, upstart as the init. The GUI is weird but it's just another desktop.

I don't use it myself but my wife's laptop does. So, example: it has no video player. Solution: Ctrl+Alt+T, just like Ubuntu. In the terminal, `apt install vlc`. Done. File associations and things just happened automatically. Once VLC was there, double-click a movie file on the local drive and it opened and played.

It's based on Gentoo but the bundled container-VM thingie is Debian.

ChromeOS is a lot more like any other distro than Android, which is different from the libc and entire userland on upwards.