This may be a minor distinction but it is easier to publish but harder to get reach when disconnected. This is important in a "allowed to try" way.
Generally for books and music the answer for "should I sell on Amazon, Apple, Barnes and Noble, Soundcloud, or my own website" is "yes".
In addition to convenience people are understandably leery about where they put their credit card info and the financial infastructure hasn't generally caught up although there are a few "one-off" credit card number generators.
