[em500]

What "the point" of headphones is, is of course subjective. But I'm going to guess that for most people, the point of using headphones is have their audio portable and/or to not disturb other people. I don't think many people use them because they explicitly like the experience of audio playing "between the ears".

As to "why", people might actually prefer the (emulated) experience of a point sound source, as it could closer resemble talking to someone physically present (calls) or listening to a live performance.