1. Key repetition - you can specify the key names once at the start of a list or map, instead of on each object separately.

2. Escaping strings - everything in a string is literal except for " which is escaped as "". This makes writing regexes and multiline text easier without introducing a bunch of different string styles or excess escaping, which I am not a fan of.

3. While not nearly as important as the first two to me, I did reduce symbol clutter when possible. Files are implicitly maps, keys don't require quotes in most cases, and you don't need commas between items.

4. Decoupling syntax and data formats - TYON has recommended formats for interoperability, but none of these are part of the core spec, so tools are equally welcome to just treat everything as a string.

The linked repo contains the spec and a cli app that provides formatting, validation, and conversion to JSON.