(1) You say – “This file is passed on to the Zamzar team, who convert in offline to the new format”.

Where is the evidence for this statement ?

(2) You say – “24 hours for a file conversion is a poor lead time to the process”

Where did you arrive at this time ? In my experience files are converted almost instantly.

One comment:

(1) You say “What if your file is misused?”

It won’t be – Zamzar’s privacy policy addresses the deletion and privacy of user files:

http://www.zamzar.com/privacy.php