Very true. Neither group tolerated supernatural propositions.
I think that Charvaka philosophers viewed the "religious experience" itself as a delusion and prayer as totally ineffective, whereas Epicureans saw the experience (as he describes early humans encountering inspiring visions in dream-states) as natural (as he did prayer), and of psychological value. I think the Charvaka opinion is a bit more like modern atheists.
Well, I guess that's one of the key points: they were atheists.
Thank you! That is very helpful