Music can also provide "online updates or other interactions": think fanclubs, exclusive gigs etc.
Say that, when you buy a M.I.A. song, you also get access to an exclusive website/forum for a month, where M.I.A. is going to blog or discuss with fans -- there you go, SaaS. The artist is not forced to do more than she used to, she's just reallocating time from "dealing with the increasingly irrelevant mainstream press" to "dealing with online fans".
The malware point is about quality. You might get the same quality from pirates, but then again you might get malware or simply a crappy rip. If you "buy legit", you are guaranteed good quality: high bitrate / lossless formats, no clicks etc.
The more I think about it, the more I see the two markets are fundamentally identical... which makes the music industry look even more stupid: with all their might and cash, they seem unable to be as profitable as some kid in California with a couple of computers.
- no malware
- possible online updates or other interactions
As long as these differences persist, your distribution method can easily add more value than the pirate copy.