Actually much of procrastination is related to anxiety, often fears of failure or success. Sometimes anxiety related to other issues. I think part of its success is that it separates the task from the feelings associated with the task. Many writers adopt a similar work pattern without this technique. They decide on the time period to devote to work--say 9-10 AM every day. They sit at their desk for that time whether or not they produce any words. They don't punish themselves for not producing. They simply keep to the schedule, and eventually, whatever the block is, dissipates. I think it works because it cognitively reframes the writing activity from a task associated with negative feelings/thoughts to a neutral activity focused upon a habit of time.

The commitment to the time period seems to require less motivation than the commitment to the task.

Whatever works.