I don't think they bought them just for the claude-code gui harness as it is now. it's to have strategic control over some software runtime they can use to do other things related to verification, deployment, and end to end value delivery. Same reason other companies are buying up dev tools.

Yeah it was a little tongue-in-cheek--I think the estimate I saw was over $100M for bun, which would have been enough to pay Donald Knuth to rewrite Claude Code, let alone AI.