Resumable uploads are another use case (see datatracker.ietf.org/doc/draft-ie...). It would be optional though. We just recently removed the digest text in the draft because it was becoming clear it needed more fleshing out and makes sense to put in its own document, likely mentioning Patched-Digest
ietf.org
Resumable Uploads for HTTP
HTTP data transfers can encounter interruption due to reasons such as canceled requests or dropped connections. If the intended recipient can indicate how much of the data was processed prior to inter...
