The Beraita states "One who ate dried figs by repaid with dates, May a blessing come upon him"
Abaye explains that it is not because he repaid with an item of greater value, but because:
He ate something that buyers do not leap after, and repaid with a thing that buyers do leap after.
Wouldn't the fact that buyers leap after dates, but not dried figs, adjust their value accordingly? Thus making dates an item of greater value?