Concretely, if Scuttlebutt uses a blockchain, then Git also uses a blockchain by a similar reasoning. I don't think the original post claiming that "there are no use cases for blockchains" was implicitly claiming that Git (or Scuttlebut) is not relevant software, just that they don't use a blockchain, because indeed they don't for any interesting definition of "blockchain".
A key difference to me between Git and Scuttlebutt, which in my (most likely flawed) view makes Scuttlebutt "blockchain-er", is the distributed nature of it. You add a friend on Scuttlebutt, and this will fetch their content from any node, and all their friends' contents. It has an "automatic replication across nodes" aspect which Git does not have.
[Disclaimer: I haven't used Scuttlebutt in a long while, so I may be getting the technical details of the friends-of-friends-replication thing wrong.]
Only if you remove all of the parts of a blockchain that make it a blockchain. The definition from wikipedia isn't a blockchain, it's a Merkle Tree. They're not the same thing - a blockchain _uses_ a merkle tree. The bits that are bolted onto the merkle tree are what make it a blockchain, and are the bits that don't provide value.
> User content in SSB is organized as an append-only sequence of immutable messages, where messages cryptographically sign adjacent messages for the purpose of guaranteeing unforgeabilitity of the sequences as they are replicated to other peers.
That's pretty much a blockchain. Of course, they don't call it a blockchain themselves, because the Scuttlebutt people are not running a grift, they're creating a communication protocol that happens to use cryptographic primitives similarly to how blockchains use them.