It is often the case that when creating an Opportunity from a Contact or Company record it is desirable to copy information in addition to the standard Contact Name and Company Name into the Opportunity record.(These are probably linked rather than copied, but that's a technicality).
For example Account Number, Reference Number, ID Status or other fields which may exist in Contact or Company records currently have to be manually copied if required into the Opportunities created from those records.
It would be neat if we could select which fields are linked yo the Opportunities in the same way we can configure which fields are linked and copied between Comany and Contact records.
Having the additional information in the Opportunity records provides much more flexibility for filtering, sorting and reporting on the Opportunity data.