So true. Well, maybe not "anything," but almost. Regardless of your views on the efficacy of Aikido against a resisting opponent, there are many great elements in it. Smoothness of motion, flowing with the opponent, concept of center, etc... These can all be used in other MA. Could you live without aikido? Sure. But when you study one art, and find similarities from another art, it helps reinforce those concepts.
Just yesterday, I was watching an ex-Gracie (personal) student BJJ blackbelt work out a little on arm options when a triangle choke is not doing its thing. Based on the top guy's exact position, one arm or the other could be taken and put in a submission lock with a subtle shift of the hips. I was much impressed of how an adjustment of just a few inches can lead from a choke with the legs to a submitting arm lock (with the legs now quietly assisting in providing body torque.)
I am trying to process this way of switching from one technique to a completely different one (without hardly moving) and how it can relate to karate. Yes, I already use this general concept in karate, but seeing it in this fashion from such a different art as BJJ puts a new slant on it. Perhaps some specific elements can be useful in some way to my primary art. As Buka recommends, I'll give it a shot.