The point is that ripgrep will give you basically all the same query features just by being fast. A more structured format makes sense, but the indexing is not obviously adding value in most cases.

The difference between grep/ripgrep and querying by field is the difference between a full table scan and an index query. Query performance is a very good reason to have databases. ripgrep is certainly fast, but it's still O(N). Doing complete file scans also trashes the OS's buffer cache.