> In my understanding the main selling point of blockchains is to outsource the accepting of state changes to a consensus protocol which does not involve human interaction/interference. And just as git a blockchain still works if only one or few actors are involved.

Agree. git works for vaguely defined rules like "is this README readable, up to date, and useful" where human input is necessary.

Blockchains can be used to enforce clearly defined rules like rules of a smart contract or rules of spending virtual money.

So roughly speaking: git = blockchain - distributed_consensus + fork_merges