You forgot to account for the time and complication in getting the sats back vs getting the $3 back. $3 ends up in your pocket by itself annoyingly, where you have to do a thing to get the sats in the wallet. In USA doing "a thing" costs more than $3 in fiat. In bitcoin the value of the time is higher. Also the risk in fiat is high, so I think It's rational and to value bitcoin above market offers for small amounts.