On the one hand, it makes sense to have a quarter of your currency. Just the natural way I'd divide a pizza is 1/2, then 1/4, then 1/8.
On the other hand, money is not pizza. As procrastination from (is it "from"?) writing my thesis, I calculated how many coins one would need in order to pay any sum between 0,01 BGN and 1 BGN. The maximum number of coins is 6, first appearing when you want to pay 0,88 BGN. The average number of coins you need is 3,41 with the mode being 3.
If I do the same calculation for USD, it will be too much procrastination on the same issue already, so maybe later :) But I have the feeling that the results will be quite similar and maybe with some small advantage for the USD since the quarter is closer to the average of 0,1 and 0,5 than 0,2.
But yes, I will be very very confused without the 0,2 coin, especially in the presence of a 0,25.
Maybe you've mentioned this but I've missed it - how are you with meters, kilograms and liters? :)
Have you already gotten used to thinking in leva rather than calculating prices in dollars?