In the construction industry, because the nature of construction borders on the chaotic, most successful construction companies have schedules. This has spilled over to any project-based business, such as manufacturing, software and building computer networks. Scheduling software, such as Microsoft Project, uses task lists with specific estimated timeframes, so that the end user can schedule disparate resources (employees, equipment, subcontractors) without too much conflict or waste. You've probably seen the output as a Gantt chart (which can be produced by the experienced project manager/scheduler on a yellow pad, without software).
The microtask approach to an individual's day, week, month, etc., is a great adaptation of this technique. A lot of people already work from checklists throughout their day. If I picture it as a Gantt chart, it's easy to understand at a glance and make use of.