What kind of ground track are these people flying that makes them need to apply power whilst still deadside?
I assume that's a rhetorical question? But if you want a reply: when one descends deadside, it may not always be possible to plan the descent so as to arrive back at the crosswind point overhead the runway at circuit height at the end of the descent. In fact, it's probably a good idea to be at circuit height a bit earlier, so one can have a good look around from circuit height. Hence one would apply power while still on the dead side in order to level off at circuit height.