Some tenants will ingest invoices in multiple avenues (email, edi, etc) and as such may utilize different matching criteria.
When addressing or action an invoice - it can be useful to understand what field is tying the invoice to the order for the following reasons:
1) Potential reporting / tracking improvements (manual, etc) for matching previously unmatched invoices
2) Keeping the invoice data as clean as possible, and only removing the necessary field when needing to unmatch an invoice which was matched to an incorrect order.