Here, here. Barty's ego is big enough as it is.
And about the "eat something else to gain power idea", I think that the energy wouldn't stick with you, pretty soon you'd burn it off, like a sugar rush. You might get more energy for the time being, and keep it long enough to replentish your own energy, but not as a way to permanatly gain more power.
About the amulet, I think that if a djinni's essence corroded the gold and jade away, the tremdous power of the spirits inside would burst out and consume
you.
"Tact is for people who aren't witty enough to be sarcastic."
Crazier than Honorius.