A good proof of concept tests the parts that are hardest to fix later, which are usually whether the tool handles your real documents and data, whether it fits how your crews actually work and whether it meets your security and IT requirements. Testing on clean sample data or a polished demo tells you very little about any of those.
It should also have clear success criteria agreed up front, like how accurately procedures are converted, how long tasks take compared with today and whether the people involved would choose to keep using it. Those answers are what make the decision about a field rollout straightforward rather than a matter of opinion.