Blockchain also means different things in some contexts. At its core, it is simply a chain of data blocks where the hash of each block includes the previous block’s hash as a salt. This is precisely what
git does to ensure a source code repository’s integrity – every commit’s diff (with commit message) is hashed with the previous commit’s hash as a salt. If you have a git hash and a git tree that matches, you have extreme confidence that the source and its history hasn’t been tampered with. This statement neither offers nor requires any external proof.
Blockchain for cryptocurrencies define additional restrictions on the content of each block, with asymetric cryptographic signatures for transferring funds and computationally demanding bit-pattern constraints on each block’s hash. The latter is what makes distributed blockchains “trustable” at scale. It can be replaced with a trusted signer (more asymmetric crypto) in private applications that don’t want to spend a fortune on electricity.
Applications like git are well-established – there’s no reason not to use them. Distributed trust is still up in the air, in my not so humble opinion.