It's actually a nightmare to get to watch movies on 64 bit systems, even more so to interact with flash games. The great thing about flash is that you load the page and it is there, you do not have to download the actual movie and play it through something else. Too much hastle for most (including me). If it were really that easy there would not be a fairly large petition requesting macromedia to do a 64 bit version.
Can't help but feel that Macromedia are missing a beat as more and more people move over to 64 bit OS by digging their heels in the sand.