OK, I'll tell you what I think it means
and someone can correct me if I'm wrong.
Interleaving combines data in a continuous way to improve performance. An example you'll probably understand immediately is the difference between having a stereo file (interleaved) or a .l and .r (left and right) file for each channel (de-interleaved). The former is more efficient in terms of disk space and in reading from the drive heads. There is no difference in the sound or picture (in the case of video) unless you also compress the interleaved file.
Given the choice and assuming there isn't a good reason to use de-interleaved (IE- a program such as DP 5 requiring that type of file) I would suggest interleaved files for both space and performance reasons. OTOH, if you have an audio file you want to separate out the l and r channels for some reason - simply renaming the de-interleaved file (dropping the .l or .r) would allow a program to open just that side of the file.
