I was originally going to say Yes. But given the conditions I have to say No.
- 2 hours to play a session in an ongoing/campaign game? That's kind of short but if it is all I had then yes absolutely I run that game.
-> But 2 hours that interrupt my ongoing game to play something random? No. Why would I do that when I can go campaign time?
- 2 hours to play a one-off game? Simply put, that isn't enough time for me. I don't care about running a random combat or clearing a random cave/dungeon. I like stories and a 2 hour one off simply doesn't give me enough time to work with. Plus it just isn't meaningful.
- 2 hours to introduce someone to the game as a one-off or side-mission or something along those lines? Possibly, but it would have to be for this specific purpose, otherwise why not just do a proper session. Plus again, it isn't very fulfilling. I've done it, and it feels like a vignette that was barely affiliated with the main game.
So, given all I just said, 2 hours as a pick up and play a random game? No, I can't see getting enough done. And even if the combat rules were infinitesimally quick then what am I going to accomplish anyway? I need a bit more time to crunch into to feel full on my RP and 2 hours doesn't provide that either.
I've done longer (usually 6+ hours) single shots like on Halloween and stuff using other systems but those weren't pick up and play, they were scheduled in advance. Even if there is learning in there, we get something done, we advance, we develop as characters and we feel it is a complete enough timeframe. I don't feel that with just 2 hours. Plus Halloween is a special occasion, thus the change of game, we didn't do it just because we were bored and had a system lying around.