Yes correct. The immutability and provenance of data are key characteristics that make blockchain useful here.
How do you ensure parity between the real world and the Blockchain?
This is the core to if a Blockchain can be trusted for anything which does not originate on the Blockchain.
No digital technology can solve epistemology and tell you what is true - but that's not the point, and blockchain applications are not unique in this.
Exactly. So what is the point? Why is this better than GitHub?
I'm pretty sceptical of blockchain applications in general because it became one of the word examples of a technobabble buzzword, but in this case I can see the argument for it.
If you think about it, git is itself a block chain, and doesn't suffer from that issue.