I mean, it doesn't even have to be true "root" access. Chromebooks have a containerized linux environment, and aside from the odd bug, the high end ones are actually great dev machines while retaining the "You spend most of your time in the browser so we may as well bake that into the OS" base layer.
I actually do use a Chromebook in this way! Out of all the Linux machines I've used, that's why I like it. Give me a space to work and provide an OS that I don't have to babysit or mentally maintain.
Been a while since I've used a chromebook but iirc there's ALSO root access that's just a bit more difficult to access, and you do actually need to access it from time to time for various reasons, or at least you used to.
You're thinking of Crouton, the old method of using linux on a Chromebook (which involved disabling boot protection and setting up a second linux install in a chroot, with a keybind that allowed you to toggle between the two environments). It was including a
Crostini is the new containerized version that is both officially supported and integrated into ChromeOS
