That wouldn't be beneficial to people who want to remain somewhat anonymous. Making them known who they are and personally sending them rewards, not to their wallet, but to that person in general, would not be beneficial by any means. I think it would be cool enough for the band to offer exclusive material on an album in general, or just give them a discounted rate.
Well... They wouldn't lose pseudonymity, I'm not talking KYC stuff or forms to fill.
More like they sign something with their Bitcoin wallet when they buy an album. Then later on, if they send a signed message from the same wallet, they're entitled to extras. Anyone know a service like that? Best would be an app that handles it at checkout and doesn't need much manual administration.