We use it as sort of a 'programmable, smart serial port'. Because RS-232 serial ports are rare these days on laptops and even desktops, its easier to use the RP

We use it as sort of a 'programmable, smart serial port'. Because RS-232 serial ports are rare these days on laptops and even desktops, its easier to use the RPi as a bridge between PC applications and electronics/hardware devices which use RS-232. The PC application connects to the RPi using a direct TCP/IP cable. Its a bit more complicated than that, but that's the general idea.