While Hagrid rummaged around for the next item, Albus considered the dilemma presented to him. James was already too powerful. To some, he was even worshipped as some kind of messiah. His ability as a soothsayer, oracle, or whatever you like to call it, was peerless. He could make predictions years into the future and was often proved right. Gifting him with an invisibility cloak, permanent or not, would be like giving dynamite to a fisherman.