I've started to learn SilverLight in order to incorporate it into my website.
After a while, while I was looking for silverlight controls in places like:
http://silverlight.codeplex.com/
And realized that everything is possible using AJAX Control toolkit (or almost everything).
Does it really make sense to use Silverlight? It doesn't work on all browsers, it causes the clients to install silverlight client and more or less gives the same end-product as ajax. What's the added benefit?
It's all about using the right tool for the job. Silverlight makes interactive type user interfaces possible.
For example, let say you want to create an online drawing application. Doing this using Silverlight is a breeze. It should save you time and lots of headaches.
"Use the right tool for the job"
The added benefit is evident for .NET shops, because .NET developers can pick up Silverlight fairly quickly and start building Web applications, so training costs are reduced. You can also reuse some (or most?) existing .NET code.
But you are right, there may not be a technical reason for you personally to choose Silverlight over AJAX or, say, Flash.