If it can ever be established what it is, a better hypothesis about what purpose it serves will follow. Until then, shit, it's all farting in the wind.
I enjoy all of the suppositions, but the best theories about it still fray at the far edges (the Standard Model still doesn't have a working quantum gravity explanation, General Relativity seems to break down at the singularity).
I'm reading up a bit on loop quantum gravity and the some of the suppositions about preons being braided space-time, which could possibly merge the Standard Model with gravity. If this model could make actual predictions we'd still be left with a Why Does It Exist question.
The "God willed it" response of theists is also a lazy incomplete answer, which never address what God is.
So until those answers are forthcoming I'm left with cramming food into my face and jerking off to porn (in no particular order) because at least those two things are defensibly necessary to my existence.