Big Tower system cases are often used to showcase the manufacturer’s technical muscle by utilizing a lot of original and proprietary features. It is not the sheer size as much as the characteristic aspects of usage that lead to this. Few people are going to use such a huge system case to assemble a home computer, let alone an office system or other type of an electronic typewriter, because the resulting PC will be huge but most of its slots and bays empty. Yes, a larger case is going to be somewhat better than the ordinary Midi Tower form-factor when it comes to cooling, assembly, and upgrade opportunities, but the size and mass may outweigh those advantages. So, a computer assembled in a Big Tower is going to have some specific purpose for which its large size will be a positive rather than negative factor.
It is in Big Towers that users usually build high-performance workstations or advanced gaming stations with top-of-the-line CPUs and graphics cards. Why? Because a large case allows to cool such top-end components more effectively. Another popular application for such computers is to be a server, particularly a file-server. Here, such factors count in as the opportunity to install a lot of hard disks and to access them easily (if a disk fails in a RAID array and needs replacement) and to ensure that all those disks are cooled properly. Using a Big Tower computer on a home network or in a small office may be more cost-effective than buying a specialized server designed for a 19-inch rack. Easy access to components, excellent cooling and a lot of free room. These are the traits of large system cases that extreme overclockers, system administrators and hardware tester are absolutely fond of.