What is the difference between the shop light fixtures and the fixtures you would find at a place such as hellolights.com, or marinedepot.com?
The shoplights are not made for wet area usage. They don't have near the wattage the others do. They are not made to be mounted inside a canopy, rather just hung from the ceiling. The reflector on a shoplight is nowhere near as efficient as the ones designed for tanks.
Having said all that, I use shoplights over 2 tanks I have in my basement, where they don't have to live up to my wife's decorating standards. The tanks are open top, with the lights hung on chains from the ceiling. I grow low-medium light plants in one of these tanks, no problem. In the long run, I suspect the ends, where the bulbs snap in, to rust or corrode, but not a problem yet. I inspect them regularly, no interest in starting an electrical fire.