All valid points, none of which negates the value of the discovery. You'll note what they're trying to do right now is not to figure out how much propolis from what source to administer in what form, but to isolate and identify the active ingredient[s] in the propolis. Once the active engredients are identified, they can probably be synthesized chemically in large quantities, just like none of us actually needs to go find a willow tree and make an infusion of boiled willow bark when we have a headache.
Re: This is rife with potential problems, though...