Adobe AIR vs. Browser Plugin/Addon

I would like to convince my client to go for an Adobe AIR and not for a Firefox/Safari/InternetExplorer-Browser-Plugin.

Can you please help me with some arguments and facts? E.g:

• AIR reaches much more people
• Development costs开发者_如何学运维 for several browser plugins are much higher
• etc.

Thanks for helping

• Air can access file system in a (normally) secure way.
• Air is a one-for-all solution.
• Air is robust and complies with stable standards. (and seems to continue on that way).

Hope that helps.