I dunno, do they serve a specific purpose?

To fill in a B side with a v similar tune? Get a well established producer to do a rmx for better recognition? To give a slightly different angle to a track? To make a better improved track (possibly dissing the original producer) that sounds totally different to the original?

If a track sounds good then why try to change it? I mean has anybody done a rmx of classical music for example or is that heresy?

Any thoughts?