It's often said we buy on emotion. Something moves us and we take action. Makes a lot of sense.
But few ask why. It's just one of those accepted things. Split tests were done to prove it, and that's all we needed to believe it.
"Can of Worms. $10"
"Catch Bigger Fish. $10"
It's the same thing as features vs benefits. A benefit raises hope. And hope raises dopamine. If you can raise someone's dopamine levels, you're in with a chance.