It does change the dynamic / comfort though. Would you rather ask AWS to please revert $5k they put on your card, or talk with them about $5k they'd like to charge you but can't?
It doesn't change the dynamic for AWS. It doesn't change for many of us. But it does for example for a student who forgot to terminate a stack and suddenly can't afford rent/utilities/shopping until the charge is resolved. These are amounts which can really mess up people's lives for weeks.