When you equip the feast on your familiar, which will often be the case in-run, the button goes away if we use setShown( have ) the way I left it. Since "use moveable feast" will retrieve it, the button might as well always appear, and be enabled.
I guess have should also be true when the feast is equipped on a familiar. I was too lazy to figure out how to check the equipment of all your familiars to see if one of them is using the feast. I'll try to work on that.
If we don't check if the feast is in your inventory or equipped on a familiar, the only downside with doing "use moveable feast" is that Mafia could try to buy one from the mall. If a user happens to have ~18m on hand, autoSatisfyWithMall set to true, and an autoBuyPriceLimit of more than 18m, Mafia will purchase it. An unlikely scenario. And perhaps even a profitable one!