Looks like psychologists have empirically confirmed a part of Zhuangzi:

But now that researchers have been analyzing those stray thoughts,
they’ve found daydreaming to be remarkably common — and often quite
useful. A wandering mind can protect you from immediate perils and keep
you on course toward long-term goals. Sometimes daydreaming is
counterproductive, but sometimes it fosters creativity and helps you
solve problems.

This brought to mind the first chapter of Zhuangzi – 逍遙遊 – which Watson translates as "Free and Easy Wandering," and Hinton renders as ""Wandering Boundless and Free."  A passage from chapter three gets at the sensibility:

Just let your mind wander along
in the drift of things. Trust yourself to what is beyond you – let it
be the nurturing center.  Then you've made it.  In the midst of all
this, is there really any response?  Nothing can compare to simply
living out your inevitable nature.  And there's nothing more
difficult….(56)

Notice that, unlike the psychologists, Zhuangzi does not worry about utility.  He would have a hard time defining "counterproductive," unless, of course, it meant taking one away from the natural unfolding of Way.  Mind wandering, for him, is not a matter of useful or useless, it is, in itself, simply reflective of human experience more generally.  We like to think that we are in control of our lives, but, in fact, we are wandering through time, subject to all sorts of unforeseen and unexpected forces and turns of fate.  And if we recognize that "inevitable nature" we can then come to "free and easy wandering"….

Now, what was I doing?….