in my opinion thin picks are for ppl with no control in their right hand.
of course it seems to be easier with a thin pick but with a thicker one you hear what you actually play WHEN you play it without any "pick-bend-delay".
you're directly on the strings and have the absolute influence on how it sounds.
with a thin pick it doesn't really matter how hard you hit (that's why it seems to be easier), with a thick one you hear how hard you're picking, of course that means you have to pick very consistently, but hey.....we're complaining about drummers not hitting hard/consistently enough all the time, so we gotta do the same!
I'm playing pickboy st-4 stone picks exclusively, (coming from nylon .63mm) and i had a really hard time getting used to that "direct playing" with a stone pick, but it definitely made me a better player with a more unique attack.
plus stonepicks sound awsome!