The most effective use of Molasses is food for your Symbiotic Micro-herd. If its being used for any other purpose its economically unsound.
Precisely. The only time I use molasses (1tbsp per gallon) is when I'm mixing my soil. I grow "organic", which is to say I construct soil and never fertilize, rather than use a soil-less substrate through which I pour a nutrient solution on a regular basis. Which is what much container-grown pot actually is. A form of hydroponics.
I don't play all that bat-shit, rat-shit, chicken-shit, brewed up tea stuff though. I'm not trying to be officially "certified organic in all ways". I just employ dry, organic ferts blended into the soil at the start, and allowed to age for a month or so. This permits the natural microrganisms in the soil to activate, reproduce, and create a naturally-balancing and fertile media that can feed my plants all by itself for the entire grow.
To that end, after I mix the soil (2 to 3 cu/ft), I moisten it with one gallon of molasses water to feed the microorganisms. Everything the plants need will come from the microorganisms.
The "snake oil industry" is going to have you paying a jillion dollars to do useless things that revolve around sugars now, though, preying on people's ignorance.