What's the purpose of calling the middle east, "middle east"?

"Middle East" was the term given to the region by Western Europeans because from their perspective, it was the Middle East. The Far East was China, Japan, etc. What is interesting is that those living in the region now call their region "Awsat al-sharqii" or, translated, Middle East! Usually when academics are referring to the region they call it the "Middle East and North Africa," so Libya, Algeria, Tunesia, and Morocco are not counted as part of the Middle East. Egypt is complicated because it usually is considered to be a part of the Middle East even though it's in North Africa (but the Sinai Peninsula is part of Asia, I believe). The question of how far East the Middle East goes is one that usually depends on who you're talking to. If you want to make it dependent on religion, then the Middle East could stretch all the way to Indonesia. Usually, though, people cut it off either to the East of Iran or to the East of Pakistan and/or Afghanistan. The purpose of calling it the Middle East is just to give the region a name to refer to instead of saying "you know, that group of countries stretching from the Mediterranean down to the Indian Ocean." There are names for almost every region of the world even if the religions, languages, and cultures are different (think of Eastern Europe - lots of different languages and a mix of Christianity and Islam plus a smattering of Judaism). The countries of the Middle East have more in common with each other than countries in other regions of the world.

well asia is huge. if you notice there's also south asia eg india bangladesh nepal maldives etc, southeast asia eg thailand singapore malaysia etc... so middle east is just another group. and since the americas is the west and everything else is the east, middle east is actually the middle of the east.