I have a few opinions on this:

1) My (and possibly other people's) last impression of this was when it was merged just based on all tests passing. In many projects, relying just on tests would definitely be reckless (not sure about coverage/quality of Bun tests).

I didn't follow much what where they doing later, maybe it is indeed good enough. For example, Claude Code using it and being fine is reassuring.

2) Making such a big decision that quickly and not (even having the time to) consulting community doesn't really inspire confidence.

3) You can be reckless even if everything ends up being perfect in the end.

Going 80mph in a city, you probably have like 80% chance of not crashing. And if you don't crash, you just had a much faster and more fun trip. Doesn't mean it wasn't reckless.