Hi, author here. It is indeed a niche thing. But there are some use cases:
* Sandbox for code you don't fully trust (e.g. download the bytecode from a web server)
* Mods for small hobby game engines
* There are many virtual machines, but not many are so small, with strong typing and no garbage collector
* Learn about virtual machines in general, but directly have a C compiler available for the virtual machine
* Sandbox for embedded applications, e.g. plug-ins for IoT applications on microcontrollers (bounded CPU time, bounded memory area, restrict access to peripheral devices)
* There is also a historical value: learn about the Quake III engine
* Sandbox for code you don't fully trust (e.g. download the bytecode from a web server)
* Mods for small hobby game engines
* There are many virtual machines, but not many are so small, with strong typing and no garbage collector
* Learn about virtual machines in general, but directly have a C compiler available for the virtual machine
* Sandbox for embedded applications, e.g. plug-ins for IoT applications on microcontrollers (bounded CPU time, bounded memory area, restrict access to peripheral devices)
* There is also a historical value: learn about the Quake III engine