This is just a theory-

DAW software actually keeps audio in a different format. When you save a seq file the audio in 'interleaved' on the disk. Each track is in systematic chunks, so the drive head doesn't have to jump all over the disk to keep streaming audio (known as thrashing). So when you copy a track you are actually copying lots and lots of chunks of data.
And different DAWs may use different size chunks in a slightly different format. So 'copying' an audio clip can be quite a task in itself, and then pasting it elsewhere could be problematic. The 'wav' format became the standard for assembling these chunks in a universal format that most DAWs can use. I think this comes into play when some people have long D&D times; the system is jumping around trying to assemble stuff and then disassemble it into the other DAW.

This is all just a guess from what little I know (which the wife says is just enough to be dangerous).

I do not work here, but the benefits are still awesome
Make your sound your own!