As has been said: If the input is an op amp (which it likely is these days), then, for a balanced input, it will connect to the + and - sides. For an unbalanced input, the - side will be grounded, or, more scarily, left floating with a pull down. Thus, I argue there is no component difference for balanced vs unbalanced inputs on equipment that provides balanced inputs (or the difference will favor the balanced side). Meanwhile, there is a clear transmission connectivity benefit with balanced connectors.
I won't discount that possibility, but without a schematic at hand, we don't really know for sure one way or another. Nor do we know if that would be the case in all instances.
It is possible, isn't it, that an unbalanced input could bypass the op amp and be essentially tied to it's output instead of going through it?
Think of it this way: if balanced wasn't the way to go, why would EVERY recording studio, live mixing desk, mastering house and any other stop in the path from performer to your house, all be using balanced interconnects?
No disagreement here that a XLR connector/balanced line is a more robust methodology. However, within the context of the question, there is no reason, IMO, that balanced line sounds better in all cases - or in any specific case - unless noise is such an issue that a balanced line is the only cure.
Sort of like putting premium gas in a car that runs perfectly fine on regular.