"OK you say you owe me a beer from last week so here's a $20 and we're even"
"Oh you need the full $27.50 because your life will collapse due to a lack of $7.50 in cash although nobody uses cash, well, there's an ATM in the lobby thats free on my network, I'll spot you $30 on the $27.50 and you owe me a can of soda next time"
The problem with a bazzilion services all trying to extort small transactional fees either short term or long term is the marketing about their fee can't avoid mentioning that the fee is really small and we're discussing fairly small amounts of money.
