People prefer dealing with units and tens of units than fraction of a unit.
ask a zimbabwe guy who paid 20 million dollars for his last meal. i dont think he'll agree.
I prefer dealing with fractions of units(Hence why coins with lower max coin supplies are better aesthetically). It's simpler. As "tss" said, would you rather pay 10million for a meal, or $2.50? I rather pay the $2.50, it's a much smaller number to deal with.