It is safe to say that human remembers name better than some gibberish numbers.
Would you use your license number, NIRC number, Birth Certificates to identify a friend or family member ? (If you do, it is kinda wierd wahaha)
Unfortunately, it is not an entire truth for computers connected to the internet. Basically, computers communicates in their native language which is numbers. How they identify each other in the Internet, it is also by numbers (more specific is IP Address).
Example of IP address is 126.96.36.199 (Guess where is this IP address pointing to).
In order to make Internet user friendly, a naming convention is used; Domain Name to be accurate.
Example of Domain Name for Yahoo is yahoo.com .
Bottom line is computer connected to the Internet uses IP Address, Domain Name is used in the front end to ease using the Internet.