Re: Why don't we practice chokes?
I'm not a big fan of chokes, but recognize them as something to have in the toolbox.
Frankly, I could see where they could be used just like other types of pins for submission.
Though I have not practiced them in Aikido, I have practiced them elsewhere, and when we do practice them, I, and those I have practiced with tap out fairly quickly. It's pretty obvious when the choke is "on," whether it be a choke to the windpipe, or choking the bloodflow, most times it's less than a second that the actual choke is in place.
Still, I usually feel like we practice them for longer period of time than I prefer.
Also not a big fan of any technique that uses a gi as an implement to do a technique (unless it can easily translate to other clothing, or a version that does not involve using the gi is also showed - whether it be a choke or any other kind of technique. That's a practical consideration, however.