The latter. For example, the concept here seems like it ought to work with the Playwright test runner for Node.js (and then you'd have compatibility with the Playwright ecosystem).
OK. Yeah so I made the decision early to go one level below Playwright and target CDP directly, because I believe I need the tight connection with Chrome/Chromium to make it as fast as possible. Also I really value the distribution aspects of writing this in Rust and compiling to a single executable with everything in it.