This is a good thing. Another advantage is control of window size and placement on the HTML page. This can be accomplished using a little JavaScript that Dreamweaver or GoLive will write for you all you do is specify what size you want. It's simple and it ensures that you have total control of what the end-user sees of your movie. In addition, you can then add an 'Enter Here' link which will open your SWF movie in a new browser window of the exact proportions you specified.
Scalability goes to hell and back.
It's important to have a movie that everyone can see and use. Start to tackle this task by having a movie that scales. When you resize your browser window, your Flash movie should scale with the window. Your user enlarges the browser window, the SWF movie gets bigger with it. User shrinks window you get the picture.