I've wondered the same thing but Gemini (free, just in the browser) helped me complete a GIS/radar app that Codex/GPT didn't seem informed enough to do. Really gave some excellent suggestions and I was impressed and feeding it into Codex we were off on a positive track again.

Then I tried to use Gemini for coding and it was like being back to GPT3 or something. Really bad. But on this topic at least it had possession or access to more knowledge than GPT.