Retro gaming is a massively popular Raspberry Pi application, and while loading your favourite old video games onto an SD card is pretty straightforward, building the physical shell of a gaming system can be daunting for those of us without 3D printers or design skills of any kind. PiBoy Mini bridges that gap by providing partially-assembled devices to their customers. The rest is BYORP: bring your own Raspberry Pi.
Sometimes the portability is nice.
There’s also a ton of emulation handhelds out there that can likely do the same thing with better firmware for around $100. Look at the RG35XX or the Miyoo Mini. Both devices can play up to PSX.