Firefox has a test pilot out of their labs called send.
It has a really great feature. The share link will expire in 24 hrs or you can set a number of allowed downloads. It defaults to 1. Once the max allowed downloads has occurred, then the link is expired. Firefox then removes the file from the server.
I believe a derivative of this idea would make for a fantastic sharing feature of nextcloud. However, unlike Firefox, the file would not be automatically removed form the server. The link would simply expire.
I could see this as a new share option. Expire after x number of downloads or the expiration date, whichever occurs first.
Would love to get some feedback from the community on this feature idea.