It's a lot more nuanced than that. If you use the free edition of Code Assist, your data can be used UNLESS you opt out, which is at the bottom of the support article you link to:
"If you don't want this data used to improve Google's machine learning models, you can opt out by following the steps in Set up Gemini Code Assist for individuals."
If you pay for code assist, no data is used to improve. If you use a Gemini API key on a pay as you go account instead, it doesn't get used to improve. It's just if you're using a non-paid, consumer account and you didn't opt out.
"If you don't want this data used to improve Google's machine learning models, you can opt out by following the steps in Set up Gemini Code Assist for individuals."
and then the link: https://developers.google.com/gemini-code-assist/docs/set-up...
If you pay for code assist, no data is used to improve. If you use a Gemini API key on a pay as you go account instead, it doesn't get used to improve. It's just if you're using a non-paid, consumer account and you didn't opt out.
That seems different than what you described.