Some settings will/can cause the file at the destination to be changed from their original contents (applying metadata). So this wouldn't work in that case.
PM could pop up an alert that it would not work with the operation at hand, or just disable the feature. (like when dealing with JPG files). I mainly deal with canon raw, so everything happens in xmp sidecars for me, so it would be useful.
This also can change when doing something like adjusting capture dates and times.
I think this is another place where PM could check to see if a checksum has been generated and then warn the user that proceeding with the operation would change the files checksum and ask if the checksum should be updated at the completion of the task.
I've seen softwares out there that can generate a list of checksums on ingest, including after verifying a correct transfer, but the list is based off the original filenames which would be of limited use to me since i rename my photos after all my cards from an event are ingested. Thats why I thought having it in XMP would be useful. So then I could ingest multiple cards into one folder, rename, do my editing, copy the folder to the backup locations and then if needed do a verification at the destination to make sure everything made it there correctly.
Happy to expand on my workflow more if it helps.