Date format problem in WP

It is very interesting to note that on Settings>>General page we can set the date format as required.
But it is not reflected in Posts>>All Posts list or even on Pages>>All Pages list.
It does not also reflect on Media>>Library pages.
So why this settings are given in WP to change the date format?
Please clarify.
Generally, people prefer dd-mm-yy or dd-mm-yyyy format. So how to change the date format and get it reflected on all sections of WP?
Please help