I don't have many freebies here as compared to some contributors, and my freebies are not any of the more popular ones. However, once a paid version of accounts kicks in at ShareCG, I can immediately consider other alternatives to place my freebies. It is simple economic behaviour.
Alternatives for this would be to make announcements in Renderosity freebie forum (where it is allowed), followed by links to SkyDrive or Gdrive (google drive), or even simply to offer my freebies at Content Paradise.
So, unless the value-add is unique and superior, it would be tough to justify a paid account at ShareCG for distributing my own freebies.