my guess?

they lose money on 200/month plan, maybe even quite a bit. So that plan only exist to subsidize their editor.

Could be about the typical "all must be under our control" power fantasies companies have.

But if there really is "no moat" and open model will be competitive just in a matter of time then having "the" coding editor might be majorly relevant for driving sales. Ironically they seem to already have kind lost that if what some people say about ClaudeCode vs. OpenCode is true...