[1] https://hyperscript.org/

- it is designed to be embedded directly in HTML

- it can listen for any event (unlike on* attributes)

- it has native support for CSS selectors: https://hyperscript.org/docs/#dom-literals

- it has async-transparency: https://hyperscript.org/docs/#async

- subjectively, it is easier to read than JavaScript, particularly for the short, light scripts it is designed for (toggling a class, etc.): `on click toggle .clicked on me`

hyperscript is more of a glue language than something I would recommend building an entire application out of (although people are doing that!)