Not the op, but this TS migration started long before AI was able to help. It was done slowly and carefully, as a project supporting millions of users should. And the benefits are very clear.

Bun’s port was a vibe coding fever dream that happened from one day to the next, with much looser motive, and yet to be proven reliable.

Bun's migration to Rust was nothing more than a marketing stunt to sell more Claude subs under the impression it can perform this kind of work at scale, assuming that most who were convinced by it wouldn't look under the hood at what really took place.

It has its merits as a proof of concept that could eventually be cleaned up and released properly later, but I can't see it any other way.

Too many see it as this miraculous one-shot and are using it as a blueprint to justify more layoffs and buzzword salad in their boisterous LinkedIn announcements about how they're "completely overhauling their strategy" in engineering. Hogwash.