A great use case that I can think of right of the bat, is protection of patient data, making it immutable once stored.
i guess the real important question is, what is wrong with current way of storing and protecting patient data? we have been using it for years and there is no problems with it which means there is no need for any change. it is basically a the database, and we don't need to change this database from its current form to a new database form called blockchain.
for instance the answer to above question about bitcoin is that we had a lot of problems with fiat aka centralized currency world including corruption, inflation, lack of privacy, lack of merchant protection with all the charge back scams, lack of security, high costs,... so bitcoin's existence as a decentralized currency was required.