I don't think it is only used for complex stuff, here are some examples they made:
http://unity3d.com/contest/flash-in-a-flash
The winner game is made by only one person in a week, IIRC, and if you consider that complex then its quality is good, too, a 3D flying plane game. You should try it, a simple short game but it is good.
It seems unity use javascript to control the flash which is not accepted by flash sites like armorgames, am I right? And it seems they are fixing it.
Here are some flash demo by unity, I just googled them:
http://www.stimunation.com/previews/labs/unityToFlashExport/unityFlashShadowDemo/
http://www.molehillgaming.com/game/unity-angry-bots
It has source code in unity page, you can try to tweak it and export to flash. I am also learning unity, and I was surprised that when I googled unity and armorgames it didn't show many results