I have a PCjr and can tell you the chicklet keyboard is really bad. It feels like typing on a pad of foam. Also while it can be wired it is a wireless keyboard that uses IR to connect. Kinda annoying since you have to be pointing directly at the PC for it to work.
Edit: found a photo of mine. It feels close to if you took a keycap and placed it on top of a Grifiti wristwrest, just a little less stiff. I think it would make a cool keyboard if someone remade it with MX switches.
The wireless also was famous for having issues.
I could be wrong but I believe it was because it used infrared.
It does, and it's really finicky. The little black disk on the PCjr is the IR sensor that the keyboard has to be pointed at in order to type. Funnily you can mess with people by pointing your keyboard at their PCjr and making it look like a ghost is typing.