Although in wall tanks or "Aussie Aquariums" as they are sometimes called, may look cool, they are really limiting. Not only are they ridiculously expensive, but because the surface area of the water is so small, oxygen exchange is limited and the most fish you could ever keep in a 10 gallon wall aquarium would be a betta or some African Dwarf Frogs. Not only that, but wall-mounted tanks can make water changes impossible, especially if the tank is placed too high. Also, depending on how deep the tank is, you couldn't expect to keep any of the larger fish (oscars, goldfish, certain gouramis, etc.)
I get more compliments from these wall aquariums than from any other art decor I have in my home (I have really expensive taste). Their customer service was top-notch answering all of my questions. They are extremely knowledgeable with everything about fish. The quality of their aquarium was superb. I also LOVED THEIR PRICE with all the free stuff you get.
In my opinion, wall tanks are just that: decoration. Unless you plan on maybe keeping a betta, ADFs, or some shrimp, I would steer clear of them. I've seen the 2 gallon Aussie aquariums sell for $100 plus dollars. For $100 dollars, you could get a 30 gallon tank and keep way more fish than you could in a dinky 2 gallon deco art death trap or a small wall mounted aquarium. It would only be worth it if you made the tank a foot or more deep, in my opinion.
You just have to think about what's best for your fish.