First off, this is one of those cases where reason should be thrown out the window immediately. You will not be able to reasonably explain to your partner why you just spent 400 USD on a chassis with the same expandability as a 100 USD variant. Those who want the Deepcool Tristellar should think more along the lines of, "I want an awesome-looking chassis with the ability to install parts as if it were a traditional ITX chassis."
The Deepcool Tristellar is obviously all about its looks, but it also manages to be surprisingly easy to assemble, while offering a good feature set for a chassis of this shape. You may even install up to five hard drives, or seven if you use the additional cage. It can also hold a long GPU and has the ability to hold a 120 mm liquid-cooling system, making the Deepcool Tristellar a good candidate for a potent gaming system. The only real downsides seem to stem from the optical drive bay as it lacks the PCB all other storage units within the chassis have and a slot-loading cover for those who want to make the Tristellar look even cooler.
That said, the Tristellar is one amazing-looking case that is not meant to be moved around a lot - based on its sheer weight alone. It is, instead, meant to show what Deepcool is capable of. The company has clearly managed to successfully combine a vision for an incredibly unique chassis with surprisingly solid functionality and excellent build quality - especially if money is of no concern to you.