Most other laptops, even low end ones, can have new life breathed into them as laptops with a lightweight Linux distribution or even take on entirely new uses like a Plex/Kodi box or retro emulator box hooked up to the TV, power efficient file server, smart home control hub, etc — basically anything one might use a Pi for, an old laptop can do just as well or better.

This is impractical on most Chromebooks because of how locked into Chrome OS they are. They're more like cheap Android phones with locked bootloaders than they are proper laptops.