It's cheap because it doesn't come with a case or a PSU, and appears to only be available through AliExpress (not necessarily a bad thing, but could make manufacturer support tricky).
A case might be nice if you prefer not to have a bare GPU on your desktop and if you want to slow down the dust buildup. SFX power supply units appear to run you about $100 for something like 650W. The power delivery is limited to 60W (in terms of how much power it'll deliver to charge a laptop), which is sufficient for many laptops but probably not all of them (I think the last generation of Intel MacBook Pros might want more than 60W).
There are some downsides to this kind of barebones design at the end of the article. The Razer enclosure (and many others?) include a power supply (and presumably fans?) as well as an outer casing that hides the cables and protects from dust and other hazards (i.e. making it safer to move around than an open design).
A case might be nice if you prefer not to have a bare GPU on your desktop and if you want to slow down the dust buildup. SFX power supply units appear to run you about $100 for something like 650W. The power delivery is limited to 60W (in terms of how much power it'll deliver to charge a laptop), which is sufficient for many laptops but probably not all of them (I think the last generation of Intel MacBook Pros might want more than 60W).