Makes mini projects possible, such as:
You want a media PC to perform a basic function like stream movies from your pc but you can't justifyy to build a pc for that job and it would take up to much room, bam there's your answer
you have a small workshop, you just bought a cnc mill, but dont really want a big PC taking room, bam there's your answer
you want a pc in your car but mini pc's plus screen plus other stuff = expensive build, bam there's your answer
you are doing R&D, manufacturing or engineering at home or at work, rather than having pc's everywhere you have one of these for a specific task, or use this as a controller for the device in development etc...