Self-explanatory; this is for slot machines found at a variety of locations, usually casinos.

This specific one is a fairly average industrial PC that is running a custom version of Debian

The state-operated slot machine company of Finland has machines which run Linux, both on the machines themselves, and the development environment for the machines.

https://nibblestew.blogspot.com/2018/02/looking-inside-linux-powered-slot.html