"Microgame", in terms of video games, can also be used to describe a game within a game (or a game within a game within a game) that is often exceptionally short - namely, a few seconds in length. Sure, it's way too short for anybody but casuals to play, and doesn't require much skill - just a bit of timing and/or luck. But they're good timekillers. If they're combined into a collection (think Wario Ware, Inc.) they're excellent for picking up for five minutes, putting back down and going about your daily business again. A distraction, perhaps, or a way of clearing the mind. Whatever you want to call it.
The best microgames (in terms of video games) are in the Wario Ware series - games that range from blowing up balloons to picking an on-screen nose. Good microgames can also be found in the Mario Party series. I wouldn't call Crash Bandicoot games microgames, per se. I'd say they're minigames. Slightly different concept IMO.
These microgames follow at least some of the above criteria. They're small. They're quick playing (and very quick learning). They're somewhat cheap. Not all of them are conflict-based, unless you call chopping up a watermelon to be conflict. And (correct me if I'm wrong) but I'm pretty sure that they're games.