Quoted from MSN site:
Note: this installation may upgrade the Microsoft Digital Rights Management components on your computer. When you click install, a unique identifier and a DRM security file are sent to a Microsoft-hosted service on the Internet. The file is replaced with a customized version that contains your unique identifier. This increases the level of protection provided by DRM.
Sounds to me as if this "music assistant" will actually increase rather than decrease the protection to where if there is any hint that you are trying to put copyrighted songs on your computer or play them from a cd that you burned with songs ripped from other cd's that it will stop you in your tracks.
This quote is from another page about it: http://music.msn.com/help/install
Windows Vista users only: If you are using Internet Explorer 7, please add MSN Music to your Trusted Sites. To do so, click on Tools in the tab bar. Click on Internet Options. Navigate to the Security tab, then to the Trusted Sites icon. Uncheck the option 'Require server verification (https:) for all sites in this zone.' Then add the site http://music.msn.com to the list.
Lastly, if you are going through any corporate proxies or firewalls this may cause problems installing. Please contact your system administrator for assistance.
It looks like the Music Assistant, in my opinion, will allow you to play songs from MSN Music site, but will stop you from playing anything else. I could be wrong.
Check out the links I gave you which also provide more links that might better describe what you are getting yourself into with the program before you leap into it.