I've got mixed feelings about this. On the one hand, I hate the added administration of overly detailed time-keeping, on the other hand, it's often too easy to employers to pressure employees to work for more hours than they're actually paid.

The gripping hand, though, is that many employers aren't interested in hours, but in results. If they just pay you for certain results, and getting those results takes too much time, is it because the employer is too demanding? Or is it an employee who is slow to do that kind of work, but still prefer it over other kinds of work? It might also lead employers to pressure employees to work faster within the hours they're supposed to work, and fire those who can't keep up. I don't think it's going to solve the problem of overly demanding employers, though it probably helps in some cases.