Rights as prerogatives of choice and control that answer that question. How do you answer it?

This doesn't help much in practice, since legal and political disputes virtually always involve conflicting rights. The political answer is that we should find workable compromises and perhaps "deals" involving conflicting rights. Referring to "positive impact we can make on society" is just a way to say that we should evaluate such "deals" and choose optimal ones.

Conversely, a "positive impact" perspective can easily account for constitutional commitments, such as limited government powers, checks-and-balances and upholding individual rights. "Governments" are social institutions, and any institution needs some kinds of grounding rules (and incentives) to channel its actions into desirable directions. Political and government agents are not magically benevolent.