Licensing music for a commercial or similar would typically cost you thousands & thousands of dollars - going out and buying a CD costs you, what, twenty?
The difference is so trivial, between the cost of an iTunes track or a CD, (where your legal rights are the same anyway; except the constitutionally questionable DMCA if you're in the US), vs. the huge jump to the cost of licensing the music for use in a commercial or public product, I don't see what the point is of making people jump through the hoop of burning a CD.
Someone who doesn't respect an artist's copyright will be willing to do the extra step - no copyright violation will have been prevented. If anyone is stopped, it's the casual home moviemaker, precisely the person who has got the right to put the music in their movies.
Trivial technical countermeasures do not make us respect copyright. Fundamental respect for musicians is what makes us respect copyright.
Not that this is (entirely) Apple's fault, it's the dinosaurs at the RIAA that really don't get it...