Perhaps O Sensei took the strikes out of (his own) aikido. Which is to say that he got good enough that they weren't a strictly neccessary component of his technique, so he stopped using them. The rest of us shmoes, however, can still benefit from knowing a bit about atemi.
About that last post, my understanding is that "atemi" as we use it in Aikido isn't neccessarily the same as it is used in other arts. I have heard other people say that atemi (at least in their style) refers specifically to pressure point striking, rather than striking in general. If this is true (and I'm not entirely sure that it is), then O Sensei may have banned pressure point striking (a potentially very dangerous practice), without forbidding the use of a well placed fist to distract someone.