To my mind, the effects of putting vegetables, wine, beer, (gasp) whiskey, or other liquids besides water in the pan are purely psychologcial. If you firmly believe doing any of these things imparts additional flavors to the final product, then it's the magic bullet that really sets your food apart.
But, if you're like me and think it's so much hokum, then you'll view such exercises as a waste. In spite of all the voodoo attributed to such measures, steam is not a flavoring agent.
That's my one-fiftieth of a dollar's worth of opinion.
Ken