“And he sinned unwittingly” — just as the “sin” stated regarding terumah requires both diminution and benefit… so here too, damage and personal benefit must occur together.
In the sugya: The gezeirah shavah to terumah further requires that the act of me’ilah both diminish the sacred item and confer benefit on the user. Mere damage without benefit, or benefit without damage, is insufficient.
Type of Learning
Hekesh of chatta to terumah — concurrent damage and personal benefit required.
What Is Learned
Me’ilah requires concurrent damage and personal benefit from the sacred object. The same dual condition that governs misuse of terumah is transferred here: the user must both harm the hekdesh and gain from it in a single act (or coordinated acts).