This is a great technique to enhance focus and spot details. After I read about it the first time I thought that must also work for other things. Since then, during particularly hard sessions of of debugging or (code) reading, I use it to physically point at code/text. Sometimes with both hands. It forces me to actually pay attention to the thing I point at. In this way it also helps spotting tokens that would otherwise be skipped, like the double "of" in the third sentence of this comment. Physically following some data, control or logic flow by tracing it out can also help to avoid losing the proverbial "thread".