The usability and the idea to don't need to go open the software every time. The size of the software, and the interfase design. Mostly is a quick solution to any mobile and game development without having to spend so much time signing in or just leave it running while you are doing other work.

AIR is a really quick way to build apps (especially games - using the Starling Framework in particular) that work across different devices with minimal additional code for the adaption. Once the initial version (say iOS) is built the app can normally be adapted easily for Android in less than a day. Desktop apps for Mac and PC are just as easy to produce too. You can use different feature requirement ANEs (Air Native Extension) to easily access native feature on mobile devices using (usually) simple APIs. There is a very helpful and friendly community too.

I loved that it provided a rich internet application experience to design to