However, I am told that one still toasts the peppercorn before grinding it, and then one uses the powder, rather than the whole peppercorn, perhaps because the seeds are so gritty. One chef told me that toasting would release more taste.

I've tried it both ways and got more flavor from the toasted and powdered version than the whole one, without having any seeds hanging around in the dish. Toasting it was a bit of a PITA, however.