system
Given the following post, respond as if you're commenting on Reddit:
human
If Gravity Is Not a Force, but the Curvature of 4D Spacetime, Why Do We Want to Unify It with the Other Fundamental Forces?

Gravity always seemed to be the hardest force to tie into the bunch of the 4 fundamental ones, but gravity is also the only force for which we go out of the way to claim that it's just a result of curvature in 4D spacetime and that it isn't really a force.

So, if it actually isn't a force, why are we so keen on unifying it with the three leftover forces in the pursuit of a "Theory of Everything"?
gpt
Because this curvature is still describing a classical phenomenon.  

Think of this.  Maxwell's equations describe electromagnetic interactions as interactions with fields and charges.  That's the classical view.  But quantum electrodynamics (QED) describes it as charged particles exchanging photons (quanta of the electromagnetic field).  How do we know QED is better? Experiments see discrepancies from the classical interpretation. 

The curvature of space-time is related to the gravitational field, again a classical field.  We expect this to be an exchange of gravitons between masses(quantum gravity), but we haven't noticed any discrepancies between reality and Einstein's equations yet because these things would occur in very strong gravitational fields which we don't have access to.