In times of stress, when a person disengages from the problem and daydreams of positive things, this gives the body and the psyche time to recuperate and gain energy. Essentially no longer being focused on the problem, the entire system can regenerate. At the same time not focused on the problem, the person automatically becomes available for information from higher sources that can help by offering solutions.
Under relatively normal circumstances daydreaming can offer clues to what the person really wants and craves, but has been too focused on other things to pay attention to his own organic, genuine desires and needs. If you pay attention to these kinds of daydreams you can take action to fulfill the desires.
Fulfilling our healthy desires adds to our well-being and health, and opens avenues for new soul expressions, which in turn brings in more satisfaction and fulfillment, and so there is a cumulative positive effect that's generated.
So if you've thought of your tendency to daydream as an indulgent, take another look. See what gems it offers.