Spear phishing for nudes/taking over the camera when your kid starts exploring porn?
Ed: in general, for a box long enough out of support - just assume there's a zero-interaction exploit for full root - and consider if you want any family member to sit on front of an internet-enabled web cam, with sound, keylogger and screen capture?
You can install your own OS on it, someone else suggested Chrome OS Flex which I guess would get you updates again and Linux or Windows should work too (assuming it’s x86, I don’t know about ARM)
The problem is that the Chrome browser version is also getting out of date, and sooner or later websites are going to malfunction or block you for using an old/insecure Chrome version.