Siebe said: “The Buddha states there are impossible places, i.e. places of rebirth in which the death apparantly cannot partake of our gifts offered. It seems only rebirth as a hungry ghost (peta) is a possible place. They can partake of offerings but other rebirths seem to be impossible places.”
This translation does not adequately express the true idea of that sutta. Janussoni brahmana asked the Buddha: “ Bhante, you know that we brahmans make offerings, saying, ‘May this food be enjoyed by our dead relatives; may our dead relatives accept this food.’ Now, Bhante, can our dead relatives actually accept this food?”
So, what the Buddha explained was that only those relatives who are born in certain peta realms (hungry ghosts) can actually accept and consume that food. In fact, the Buddha said that those particular petas get their food only that way. If they do not get such offerings, they just go hungry.
On the other hand, beings in other realms cannot get their food that way. For example, one born as a hell-being, an animal, a human, or a deva cannot get their food from such offerings, because that is not how they get their food.
However, this has nothing to do with giving merits (pattidana/punna anumodana). All beings can benefit from that; see, “Transfer of Merits (Pattidāna) – How Does it Happen?“.