Me, Myself, Why?

Why do some people, when referring to themselves, use the business letter closing “yours truly”?
Curious Person: Who was at the party, Desmond?
Jackass: The usual motley crew. Jasper, Caroline, that guy we call Viper, and yours truly.
You know what? From here on out, I plan to refer to myself as, alternately, “best regards”, “sincerely”, “best wishes”, “respectfully yours”, or, the ultimate, “cordially”.
P.S. “Myself” would not be a proper substitute for “yours truly” in the above example. Just in case you were wondering.