It wasn't that uncommon - most of popular adventure games (and probably others too, but I just happen to know about this genre) worked as VMs or interpreters (SCUMM, AGI, SCI). Helped a lot with portability, which was desirable at that time when games were being released on various platforms like IBM PC, Apple, Amiga, Atari, Commodore 64, NES...

And thanks to that we have ScummVM now.