Domain names are not case sensitive and so the web browsers change the letters even typed in capital letters to small letters for many reasons.
* Domain name (Name.tld) is not case sensitive
* But, the complete URL (the path after the domain name) may be case sensitive if it's hosted on a Linux/Unix server (name.tld/Capital) is case sensitive. Trying to load name.tld/capital will result in page not found.
But may be a small code can be created by browsers that the developers can include in the websites to tell which letter(s) of the domain name should be capitalised and browsers just follow the same to display the particular letters of the domain name in capital letters.
But no one is going to see the url and they are not going to work on it as it will only increase the size of the page little more and in turn may increase page load time.