Bukhari

Hadith Commentary:

That is, its consumption is now permissible for us.
Because the issue is that when charity, zakat, etc., are given to a deserving person, then he may use it in whatever manner he wishes.
He may feed it to any rich or poor person.
He may also give it as a gift.
Now it has become his personal property; he has become its owner.
He has as much freedom in spending it as an owner would have.
To accept a gift from a poor person for the sake of consoling him is even more meritorious.

Hadith Commentary:
(1)
When charity (sadaqah) reaches its rightful recipient, it is no longer considered charity, because the transfer of ownership brings about a change in the status of the item. The case of Atiyyah (radi Allahu anhu) is similar to that of Barirah (radi Allahu anha): when the charity reached them, and then they sent it to Aisha (radi Allahu anha) for her service, it took the ruling of a gift (hadiyyah). At that point, it was no longer charity, and thus it became permissible for us.
(2)
It should be noted that accepting a gift from a poor person, in order to comfort and honor him, is a cause for increased reward and merit.