Quick answer
Private deployment exists for one reason: some documents are not allowed to leave the organisation's infrastructure, regardless of how good the public service is.
What changes under private deployment
- Document data stays within your own network or infrastructure rather than transiting a shared service
- Storage is your own, so files are held where your policies require them to be held
- The translation pipeline can be audited, so you can show what was processed and when
- It can be integrated with internal systems rather than used only through a browser
When it is worth the setup
- Documents that are confidential, commercially sensitive, or under contractual restriction
- Sectors where data residency is a requirement rather than a preference
- Internal legal, technical, and financial material that cannot be sent to third parties
- Organisations that need translation available to teams without each of them uploading files externally
What to work out before deploying
- Which document types actually require it, since running everything privately is rarely necessary
- Where your storage will live and who administers it
- How users and teams map onto the deployment — see organization accounts
- Which models are available in your environment, since this depends on the deployment
Bottom line
If your constraint is "these files cannot leave our network", private deployment is the answer to that specific problem. Get in touch with your requirements and environment to scope it.