Talking about unbeatable advantages, here are a few for Flash
Vector graphics are so well received because of the fact that they look crisp and unaliased regardless of the screen resolution you have or how you resize the image. This is due to the fact they are not image files like .jpg or .png, but rather pieces of code which are rendered immediately in the web browser. When combined with the strength of a flash template, the consistent lines and crisp animation are a treat to look at.
Embedable videos on Youtube and webpages is merely another thing Flash is well-known for. Using the plugin, the videos on a webpage can be rendered regardless of the Operating System.
This has long been the strong suit for Flash. Flash templates or Flash webpage designs look and feel much more live and make the webpage stand out from the others largely due to animation effects.
Compatibility across Platforms
You probably know how many web browsers exist these days and Flash templates based sites are comfortably viewable on majority of them. The hassle-free plug-in for Flash replaces all the frustration of working to make a web site behave itself in Internet Explorer, Firefox, and Chrome.