Its not necessary, but it saves a lot of time when dealing with people not familiar with the names. Its so much easier to say my name is Alan and be done with a telephone agent than to spend a few minutes spelling out Y E C H E Z K E L. No, thats Yechezkel, not Haskel. Thats Y as in Yo Yo, E as in Edward C as in Cholent, what you dont know what Cholent is, thats spelled C as in Chrain, oh forget it, whatever you put after the E is fine by me, lets go on to the next letter….
But in todays society if someone can show up and introduce themselves as Tandighruvisavatsili Ranghichasvidranmiranai, then you can introduce yourself as Yechezkel Schwartz or Levi Yitzchak Cohen.