Could O.K.R.'s adequately replace the traditional competency framework for measuring performance?

Instead of evaluating each an every employee on some standard set of competencies (whether dictated by level, role, function, etc), is there any merit to scrapping that approach to focus more on tailoring the performance plan for an individual based on distinct and discrete goals for that individual during the year. Their evaluation is then based on their demonstrated success/progress toward those specific goals (all of which link very closely to what the overall Company goals are) - not a standard set of competencies which may or may not directly apply. This would be more of a results based measurement approach - some refer to it as OKR (Objective and Key Results) - Google uses it; I think Intel does too. What are the ups and downs to this approach?