The value of selfish kindness
EthicsComments
But what about the part where the motive cancels out the result... if the money still buys the food, does the motive actually change the physical reality for the hungry person?
This ties into that thread on gratitude debts from earlier this week. While the physical benefit stays the same, a selfish motive often creates a social ledger that the receiver is then expected to pay back.
Utilitarianism supports the OP here. Since internal motives are unobservable and unquantifiable, the only reliable metric for value is the measurable increase in wellbeing for the recipient.
Consider a scenario where the selfish motive actually ensures the kindness continues. If a person is driven by a desire for prestige, they might be more consistent and long term in their giving than someone relying on a fleeting feeling of empathy.