Altman has stated in interviews they are considering releasing the un-tuned "base model", but they haven't done this.
For GPT-3, you can get models on the API via the "completion" end points (includes base models) and via the "chat" endpoints. For GPT-4, they've only released the latter.
So my point is: You can absolutely use ChatGPT to build an opinion on what GPT-4 is capable of. Arguably even better than on the Playground, as the ChatGPT frontend supports a bigger token window than the Playground frontend (8k vs. 2k). Of course the actual API supports the full token window (and if you're off the separate waitlist for this, even the full 32k). But it's still the same model.
Altman has stated in interviews they are considering releasing the un-tuned "base model", but they haven't done this.
For GPT-3, you can get models on the API via the "completion" end points (includes base models) and via the "chat" endpoints. For GPT-4, they've only released the latter.
So my point is: You can absolutely use ChatGPT to build an opinion on what GPT-4 is capable of. Arguably even better than on the Playground, as the ChatGPT frontend supports a bigger token window than the Playground frontend (8k vs. 2k). Of course the actual API supports the full token window (and if you're off the separate waitlist for this, even the full 32k). But it's still the same model.