The one use
The one use I could imagine (apart from crypto coin) is a decentralised register of academic achievement such as degree certificates. There are many many issuing authorities (universities and colleges) but once issued the credentials are fixed and for life. Validating someones academic credentials, especially internationally, is currently a chore that requires requesting a transcript from the institution either by an employer or the (former) student. For the university this is a pain in the storage as well as an, albeit fairly automated, admin chore that they could really do without. I could see blockchain potentially working in this space,