Well, my friends old Sandy Bridge system has a Celeron. I must agree it's trash (a 1.6ghz dual-core, when the contemporary Core i3s were 3ghz on up? Bleh.) But he's running Linux so I have not had to deal with problems because of this, it plays videos (including HD) fine, surfs the web fine, and plays some older games fine under Wine.
Disagree entirely about only making performance chips -- Linux is not the CPU hog Windows is, there's plenty of uses for a cheap'n'cheerful CPU where I would not want to be forced into buying a higher-end CPU that is just going to sit there largely idle. In addition, on a notebook, since ARM notebooks are not common yet (Ubuntu runs great on ARM), you've got to deal with the power hoggery of Intel or AMD; at least the low-end Intel CPUs use somewhat less power.
To be honest, I'm not a fan of calling them Pentium and Celeron *OR* calling them "processor". I would think the sensible thing would be, if they are below the Core i3 specs, call them Core i1. Why not? BMW makes and sells an M1 that is smaller than the M3.