I shall explain once even though many people have done it already.
Many countries don’t get the 60 day free so still need to apply for the 60 day visa. Also by having the actual visa some people believe it will guarantee them entry so prefer to spend the money.
Your mistake was thinking the 60 day visa was for 90 days because it is VALID for 90 days. I understand English is not your first language so just accept your mistake and move on.
I would rather be a sanctimonious cunt than one of those guys that think they know everything and like to tell people but are generally just wrong. We all know those types of people right?