Not so much that as simple availability. I already had the seed and celery for other reasons and didn't feel like buying fresh cilantro just for the one dish. Also, the taste doesn't bother me much, but I know that some people have a strong dislike and since I don't know the preferences of all the people I'm feeding I figured I'd be conservative. (I also substituted spearmint in a couple of places for pennyroyal since I've run into a startlingly large number of people with a strong and IMO slightly irrational fear of it, based on warnings about the effects of medicinal-strength doses of pennyroyal oil.)