"Do your own stuff when you've finished your assigned tasks" is dicey for a couple of reasons:
1) You could be in a position where the work "never" ends. For sure, there are a reasonable number of tasks expected to be done at the end of the day, working some fraction of the day's butt-in-seat time; and when they're done, the business runs smoothly. However, recognizing this, businesses will add tasks that could be automated or designed away (e.g., answering the same inane help-desk tickets, which pile up constantly), because they "help" to secure an employee's "engagement" when they'd otherwise be free to study, optimize their performance, or simply socialize. If you're seen doing any of these, rather than the assigned tasks, you'll be docked.
2) It's difficult to bounce between tasks, including from your work-work to your personal work and back again. This is a sure-fire recipe for not being able to maintain, or even cultivate, focus. To add insult to injury, workers are often dealing with a scenario where "availability" is required of them to mask inefficiencies in the business' management or administration. This task could be done remotely, that one could be automated, a third could be grouped with a fourth if someone twisted arms to get the necessary data earlier (as has proven possible on days before a holiday). Allocating the 2 or 3 hours of the day not spent directly on work tasks would then be possible, but not when they're spread out over the course of an 8+ hour day in 10 minute chunks, or eaten up by busy work. "Hurry up and wait" is a productivity-killer.
1) You could be in a position where the work "never" ends. For sure, there are a reasonable number of tasks expected to be done at the end of the day, working some fraction of the day's butt-in-seat time; and when they're done, the business runs smoothly. However, recognizing this, businesses will add tasks that could be automated or designed away (e.g., answering the same inane help-desk tickets, which pile up constantly), because they "help" to secure an employee's "engagement" when they'd otherwise be free to study, optimize their performance, or simply socialize. If you're seen doing any of these, rather than the assigned tasks, you'll be docked.
2) It's difficult to bounce between tasks, including from your work-work to your personal work and back again. This is a sure-fire recipe for not being able to maintain, or even cultivate, focus. To add insult to injury, workers are often dealing with a scenario where "availability" is required of them to mask inefficiencies in the business' management or administration. This task could be done remotely, that one could be automated, a third could be grouped with a fourth if someone twisted arms to get the necessary data earlier (as has proven possible on days before a holiday). Allocating the 2 or 3 hours of the day not spent directly on work tasks would then be possible, but not when they're spread out over the course of an 8+ hour day in 10 minute chunks, or eaten up by busy work. "Hurry up and wait" is a productivity-killer.