Playing FLV in Silverlight - What is it for?

What am I talking about?
FLV is, roughly speaking, a video file format played by Flash applications on the Internet. I want to teach Silverlight applications to understand this format in the same way Flash does.
The purpose of this message is to understand the need to use the FLV video container in Silverlight applications. I also want to note that with Flash I worked enough and ate a dozen of spoons of tar and only a couple of spoons of honey. And finally, do not judge strictly, this is my first post.

So, let's begin.
First, we define the terms.
Flash is a program written using technologies from Adobe Flash.
Silverlight or simply SL is a program written using Microsoft's Silverlight technology.
FLV is a video / audio container played by Flash.
MP4 is a video / audio container, perceived by most existing players.
Smooth Streaming is a technology that allows you to play videos with varying quality depending on network bandwidth.
RTMP is a special protocol for exchanging data between a Flash application and a server.
.NET is a runtime and application development platform from Microsoft.
Visual Studio is a development environment for Microsoft's .NET platform.

To begin with, we will think that using SL, it is possible to play FLV video. The question arises, what is it for, if you already have a huge selection of players written in Flash?
There are several reasons for this:

1. playback of one base of video clips for users with Flash and SL applications, i.e. universality;
2. SL provides a more flexible architecture for writing video player. In short, on SL with a video stream you can do something, which is not possible in Flash. Users viewing video in SL will have some advantages over users of Flash players, namely: Smooth Streaming on the client side, no RTMP protocols, download the video just a minute ahead, protection from gaps in the network, downloading video in several streams - especially important , and a lot of what I have not yet invented;
3. Why precisely FLV, and not, say, MP4? Because, in my opinion, the FLV format is more suitable for transferring streaming data than MP4, and also the very clear documentation of this format plays its role;
4. SL is a rapidly developing technology, the support of which must be done now, in order not to be left behind, but also you should not forget about the majority of users who have not yet installed the SL extension;
5. As a programmer for .NET, it is much more convenient for me to develop applications for SL using the familiar Visual Studio programming environment, and the familiar, albeit cropped, set of classes and libraries.

Of course, if you want to make money, then these reasons are not enough, but good things were not done for profit.
I would like to know your opinion about this development - the usefulness and prospects, as well as possible pitfalls, such as Adobe’s rights to the FLV format.