None for plants, but it's awfully good for humans. I can't recall what I've read of chamomile, but let me tell you what I'd read some years ago about using spent blossoms, I think it was @Bulldog11 who originally posted about it (that I saw). I don't remember what blossoms he said he used, but I used my spent Camellia blossoms on my rhododendron that wasn't blooming and got it to bloom. Each part of the plant can/may concentrate certain nutrients and hormones in particular areas, and so I chose blossoms in the hopes they would have a good amount of P and K.
So! My answer is I really don't know, but I say try it! I seriously doubt it'll hurt a thing, at the very least.