Can anyone elaborate a use case for something like this? I’m guessing there’s some blockchain connection but it’s not immediately obvious
You can see how with just the effort repointing queries a reporting app could show the real world and the world you are modelling.
0) The most obvious use case is to replace git, because git proper doesn't handle big files very well, let alone bigger than RAM structured data. Mind the fact you might still need an ad-hoc solution for binary data. WT does have a limitation on value size.
1) There is various data science uses cases, like sharing data [0] or A/B testing stuff.
2) Anywhere you need an audit trail .ie you need to look back at previous states, whether it is for debugging purpose or domain logic
versioned datastore is a compromise between event sourcing (pure log) and non-versioned databases.
[0] Collaborative Open Data versioning: A Pragmatic Approach Using Linked Data
[1] https://en.wikipedia.org/wiki/Audit_trail
edit: cosmit.
3) Take a copy of the data store offline, and later merge it back into the online database
Manually resolving conflicts is fine. The alternative is to rebuild a system on Couchbase/pouchdb, or rewrite on event sourcing, neither of which - when the system otherwise lends itself to RDBMS - is my choice.