All of these "side quests" (and especially this one) are attempts to build a walled-garden.

Especially this. OpenAI will host it. OpenAI will throw "Sign in with ChatGPT" there. "Apps" will be built that depend on end users ChatGPT "connections". The app will fundamentally not work without an end-user having a ChatGPT account/subscription and "connected apps".

Having "the best model" will absolutely not support a $1T+ valuation. Owning the activity of 25-50% of internet users (assuming a split between OAI/Anthropic/Google/maybe-Meta), is.