API calls are not used to train models, unless you opt in within data controls of the platform account, if that is your concern.
Model inputs are still subject to retention for safety for a period, and you would still have any other general concerns about any organizations to which you provide data without ultimate observability of your own private servers. Working with classified documents, for example, may not allow you to use a platform where any support personnel can look up your request IDs. Or hackers.
How many API credits you would actually get is not disclosed, you’d review your contract and sales agreement.