A method of behavioral change characterized by small adjustments rather than rapid transformations, because you can’t really make big changes in one day.
Honestly, it's pretty effective provided that there are no deadlines other than death, or the deadlines are far away, otherwise focusing might be more effective.
Micro-habits (things that are not gigantic goals such that you do not flinch due to the distance) help with this. One small thing done towards a goal every day will eventually compound to a big thing. On good days, you may also end up doing more than your micro-habit, and psychologically, it helps sustain the behavior for a long time!
In fact, due to the nature of this, it is slower to see your first result than if you were focusing on one task totally. However, for multiple tasks, due to the interleaving preventing fatigue, the total efficiency might actually be higher.