If you absolutely do not need to use Silverlight, and you cannot do this with HTML, do not use Silverlight. This is useful for some functions (video, etc.), but remember that many people (for example, me) do not have Silverlight installed, and if we visit a site that says: “you must install Silverlight,” our answer is “ you must be crazy. " Each of them will lose a user or a client.
I visited one or two sites (mainly Microsoft) because I needed some information or something that interested. The developer decided that I was not allowed to have this information unless I installed Silverlight. I went to another place to find this information.
So make as much website as possible in HTML, and if you need to use Silverlight, suggest an alternative to HTML.