Although your view is sound a good it's not advisable.
If your window is one big tga graphic, then yes, if your window is made up of parts the no.
Reason: Memory, Text takes up tons of less memory to then pictures. But if you already have a graphic behind where your putting the text well heck, do it. Just bare in mind that the fading effect will effect your embedded text as well.
Just my 2 cent theory, you don't have to agree with it, I won't loose any sleep over it.
Nodent