I suppose, strictly speaking, 'balanced throttle' would mean no drive and no overun with consequent engine braking.
But, as R1NGA is quite right in saying, it is all about weight distribution, when accelerating the front end gets lighter and the rear heavier, with the effect that you get less front end grip, ie possibly understeer when cornering, and better traction, until too much power is applied and traction is broken. By the same token, getting right off the accelerator, will cause engine braking, putting weight onto the front tyres, which could give better grip, but lightening the back tyre[s]. which may result in lift off oversteer, in extremis.
So balanced throttle will keep the weight distribution pretty much in balance.
And, finally, to make an attempt at answering the question, I honestly haven't notice much difference under various throttle loadings, balanced or otherwise.
