Hoi,
When we have no data at all, we have a 100% failure rate. When we import data from Wikipedia we improve on that. When we copy by hand there is an additional failure rate because people make mistakes.
Given the ever increasing number of external sources that are referenced to from many items (often these references are the only statements), it should be not that hard to create bots that compare "our" data with "their" data. The discrepancies found indicate that their is a reason for attention. When there is no discrepancy it can still be wrong..
My point is obvious; adding data to the best of our abilities is to be preferred over no data at all.
Thanks,
GerardM