I would guess there are 2 levels of application here.
There is the code and the requirement that the 64 bit implementation be such that it takes the software to a place where it will operate faster and with less demand on the resources.
Then there is the FACT that the compiler must be available to take the source code and do the 64 bit thing on compilation after it's written to take advantage of dual core, quad core, and the extra memory available.
It sure is tempting looking at fairly large flash drives and wondering what if I put all the O/S plus band in a box on a flash drive, what would happen to the times?
Right now on my laptop it takes quite a while to get a song going with 4 RealTracks.
How long with all on a flash drive?
How long if the program was 64 bit?
How long if I got a screamer of a system.
I have, for the last 2 years, had the program on a big HP media system on Win7. What's next after 64 bit Win7 with 8 gigs of memory and a TB of space?
Can I run Biab and a slideshow on a projector at the same time without problems? (Stay tuned!)
As I said before this is curiosity based as much as anything.