Yes, result based measuring is the best method of measurement for employee productivity. It's simple, accurate, easily measured, and useful for productivity predictions. It also contributes to a more relaxed and stable work atmosphere. Also it forces employers to have clear, measurable goals and expectations. Which too many are lacking.

Timing screentime is just a silly game that over-controlling people feel like arbitrarily playing. It's inaccurate. People can spend all day working and get almost nothing done, and the other end of the spectrum exists too (which is punished by this method). It's also demeaning, people should be respected not treated like children and micro-managed.