A lot of people need more than one email account.
For example, I have an AOL account that I've used since 1991, and that many friends (from all over the world) and family use to communicate with me.
I run two businesses and have two email accounts, one associated with each of them.
I have an email account that goes with my franklinveaux.com domain, which is my main email account that I use for 80+ percent of my email.
I have an email account not associated with any of those accounts that I use for novels I write under a pseudonym.
And, finally, I have an email account that's just for tech problems/moderator contact for Fine Tuned Mac.
I have an elaborate system of folders that keeps them all separate, and rules in Mail that automatically sort incoming emails into the proper folders. I have not yet upgraded to Mavericks on my main production computer because a serious and well-known bug in Mavericks can and often will completely trash your email, in some cases deleting some or all of your saved emails, if you're using more than one email account. That is, in my opinion, an issue that should never have made it into the final release version of 10.9.
