Realtime feedback empowers people to change.

You hire people because you believe they can succeed, and in the vast majority of cases, your people want to excel, not just meet expectations. You've committed to them, and the've commit to you. There's a responsibility for both parties to nurture that relationship, and that takes communication. Constant open communication when it matters, not saved away for discussion six or twelve months later. Put the feedback mechanism in their hands and let them manage their own growth with help from the people best qualified to help, their peers.

The alternatives have failed us for decades.

People without shared purpose will invent their own, as well as their own measures of success to align with those. This has played out for decades. Teams split by problematic personalities pushing personal agendas that undercut others, or don't align with the way the organization wants to operate, are a real hazard. In such cases early detection and correction is critical, but it's rarely achieved. If the signs have to accumulate for months before they're addressed it's simply too late to change behavior. When people aren't even aware of how their behaviors are percieved there's no way they'll make any adjustments at all, which sets everyone up for failure.