Silverlight and Adobe Flash are two completely different technologies. As it's Flash Player for all websites, many developers choose the approach to Silverlight embedding. This means that if you want to view certain content on a website which has been built using Silverlight technology, then you will need the ActiveX, just like in the case of Adobe Flashplayer. As Silverlight belongs to Microsoft, you will notice that almost all related websites to Microsoft use this technology and for a rich and beautiful experience over the web it is recommended to keep the both ActiveX installed.
