I have never heard of, nor seen this product, but i would say it would not be beneficial to growing marijuana, mainly because marijuana likes a wet/dry cycle (when grown in soil) and keeping your root zone wet 24/7 not only slows growth, but invites critters.I will add, I am not experienced with the product... Just basing my opinion off what I do know about marijuana cultivation.
I once considered using multiple watering globes that would do the same thing (keeping the soil saturated) but came to the same conclusion that i came to here...not a good idea/
same issue with the water mat. You want your runoff to go away from your plant, not the other way around....people do bottom feed, but they don't do it so it stays wet 24/7. When the medium is saturated the soil has very little oxygen in it, so that is where problems stem from...
I could see the mat being helpful if you were to go on vacation or something.
Sure it would be nice if we didn't have to have our hands in the plants every day, but that is key to good yields, and even better smoke.
good luck!
I just revived this free bee through the post from anglian water ( how do they know ha ha) could we use this for our special plants and anyone heard of it I haven't opened it yet to see inside packet to inspect it as got nowt to use it for at mo anyway some pics and if anyone wants to get a free sample get in touch with Anglian water I suppose 
gosh I just walked in apartment an they smelling good so sweet love it