The safest approach is to decide based on “data sensitivity × compliance × auditability”:
- Choose on‑prem/private: tenders/IP/contracts/regulations, internal operations data, customer data, or any sensitive content; auditability and strict access control; no data egress allowed.
- Choose public cloud: public information summarization, general writing/brainstorming, non-sensitive tasks with no audit requirements.
- If you must use cloud: treat “isolated environment, PII masking, audit trails, and no-training terms” as minimum requirements, and document data boundaries via NDA/DPA.