I get excited about different laptops occasionally...and then I remember that I won't have a trackpoint if I switch to a different brand, and I get disappointed. Literally happens every few months.
I think they were competitive with old touchpads (and probably the ones you still get on cheap laptops) but I expect all the people above praising them have just never used a modern Apple touchpad. Far superior. It's not even close.
There's a good reason nobody makes them anymore.
They don't have a learning curve in the sense that it's difficult to make one functional, but when I did try a trackpoint I felt it terribly awkward and imprecise. I'm not at all surprised that there would be a transition period after which trackpoints at least felt better to use.