MacOS is built for people that use pointing devices, is not optimized for keyboard usage, it makes no sense for example to show Finder when you alt+tab even if is closed. If you use 2 active apps only and a bunch of background apps (a developer setup) it makes zero sense to show you these in alt+tab. This app is also configurable to decide which apps you show, not to add that will show a screenshot which is way better than an icon. This app, advertised here is godsend for Linux and Windows users that are forced to use macs at work.