In the previous post I mentioned about pressure points, but I will paraphrase it again on this one.
One of the main things on both joint locks and pressure points is everyone has a different tolerance level to the pain. Some people are called "non-responders" and don't feel it, I am one of those and my dept. Sgt. even joked I should be drug tested because I could go thru the pain. But, with alot of those nerve strikes I would still get the motor dysfunction that the technique was designed for even though the pain didn't hurt too much.
As for the place of them in Aikido, I think alot of that depends on your Sensei's view of atemi in general.
There are some good books out there on pressure points, the main thing is it should teach the spot, the angle, and the method to activate the point. Then get a person and experiment with them and work them into your aikido techniques and realize what ones are open for strikes as you go thru the techniques.