[niktezak]

The API allows you to fine-tune existing models on your own dataset [1]

[1] Cf second paragraph of https://openai.com/blog/openai-api/

[YeGoblynQueenne]

"fine tuning", i.e. transfer learning is still limited by the training of the original model.

For instance, if the original model is trained on English text exclusively and you want to fine-tune it on Greek text you are S.O.L.