I do think human-readability is a useful feature, to some extent. Human operators should be able to sanity-check individual components of the system for correctness, and this is so much easier if intermediate data formats are "human readable" (which I would extend as far as .sqlite, assuming a straightforward schema design).
Yeah I’m not saying you shouldn’t have a file that is possible to sanity check if that’s important to your system, but I would say (contrary to op and many comments) that we shouldn’t design around that as the core feature assumption. We don’t have trouble sanity checking our normal db tables so I’d imagine that any format that has a reliable way to see the loaded-in-memory representation would meet the same level of sanity checking.