I would say it is an exercise that can help you to achieve to be in the present more often, but to me, being "in the present" means I am not distracted by anything other than what I am focused on. The moment I also think about what I am focused on, I add a "meta level observer", thus I'm not fully present: I am no longer just in my experience of the presence, I am also in my thoughts, or already in a reaction to my experience.

A body scan can serve this: by checking out everything that I feel and think, I can identify and address irritations that would potentially cause me to not be fully present later. Like a checklist. Safety? Check. Where am I in space and time? Check. Thirst, Hunger? Check. Need to go to the toilet? Check. Comfort? Check. Now, after all that and more, I can better aim to relax into being fully present, ignoring everything that would cause distractions, like thoughts. During the body scan however, I am not fully present.