Firstly here is a great tutorial on Silverlight Application and Webpart in Sharepoint 2010, but BI folks who might not have any programming knowledge about .NET might not be able to understand a major part of it. Still they can go thru the summary that I have explained in the below points.
1) Silverlight Applications can be developed using Visual Studio 2010, which also has got interfaces to develop and deploy it over sharepoint.
2) Output of any Silverlight application would be a .XAP file, which can be thought of as a .EXE or .DLL file that comes out of any .NET based application.
3) Sharepoint 2010 has a separate webpart for Silverlight called the "Silverlight Webpart" under the "Media and Content" category. And this webpart just need to be provided with the URL of the .XAP file which can be hosted on Sharepoint 2010.
4) These Silverlight Webparts can also be customised or enhanced, to suit the needs of the solution. This can be thought of as a custom component which we can develop in SSIS using script and .NET.
5) With the latest version of Silverlight (version 4 I guess), we have the facility of installing and executing Silverlight out of the browser as a separate application, without the need of any browser.
Dundas Dashboards and Telerix Dashboards are providers of Silverlight based dashboarding solutions. Let's take example of Dundas Dashboards. Dundas Dashboard Viewer is a silverlight application, which can be thought of similar to a report viewer control that is available with any .NET application. Now this application is a .XAP file, and this can be programmed to view any Dashboard components or application developed using Dundas Dashboards. Host this .XAP file in a Silverlight Webpart in Sharepoint 2010. When this webpart is made available to any page on Sharepoint, this would make the entire dashboard available to any user.
By the above explanation, the point that I intend to make is that though BI folks would not take much interest into Sharepoint 2010 or Silverlight, it's better to keep information about components that we require to integrate parts of our BI solution into sharepoint.