@Enchantress, I did search, because I had never heard about spheres being problematic. I found the
PetHelpful.com article you quoted, which I think everyone on this site would agree with.
This is a 15ish gallon tank that has a proprietary filtration system which aerates as it filters. The manufacturer makes tools especially designed for cleaning and otherwise maintaining an aquarium with its unique shape. You really should read up on Biorb. It's really neat stuff.
In terms of comfort for the critters, 90° angles (or 60°, if you're into that sort of thing) are far less natural than a curved wall. This is why many large public aquaria have cylindrical displays.
In terms of visual distortion, any time someone or some critter is looking through both water and air, their vision will be distorted through refraction. Fish have excellent eyesight, and yet looking outside of the water is not what their eyes are designed to do-- with the exception of archer fish. And *their* eyes aren't designed to look through glass or acrylic in addition!
It very much sounds like the conclusion that Biorbs are bad for fish is a thought experiment expanding on the PetHelpful.com article. It's okay to admit that you hadn't previously known about this particular type of aquarium. We all agree that bowls are bad, but the reasons do not extend to a large, properly heater, filtered, and aerated tank like a Biorb.