Hey, I know this is a bit old, but to clarify the reason is bioavailability. Your body absorbs liquids lot quicker than solids or semi-liquids. Also, the way these drinks keep the thc in solution tends to be a fatty substance like MCT which is both more bioavailable and spreads out the thc, allowing it to be absorbed easier and quicker. This is especially needed in the legal side where equal dosage must be kept over the entire liquid