As thread title suggests, I'm just wondering why hydroponics seem so interesting to cannabis growers. Seems like they frequently talk about going to hydro stores or stuff pertaining to hydroponic growing.
One should point out what "hydroponics" could or should mean.
Strictly speaking, if the growing medium is inert, or if there is no medium at all, then it is a hydroponic setup. Growing in coco/perlite or vermiculite/perlite or rockwool with mineral fertilizers is all hydroponics.
If you hand water with Jack's 3-2-1 in coco/perlite it's a hydroponic grow.
The reason why it's appealing (not just for Cannabis, but also for regular cash crops), is the increased yield, vastly reduced water consumption, and improved control over the grow environment.
In my experience it's a lot less messy than a "traditional" soil grow, and it's also not difficult (if you have a pH test kit and a measuring cup for the nutrients).
Why not just grow in dirt like with any other plant?
As others have pointed out, a lot of plants are grown hydroponically at scale.