Many others, e.g. Google and NVIDIA, have also released such BASE models.

For those with the knowledge and resources needed to finalize the training, BASE models are much more useful than completely trained models.

BASE models are the next best thing after truly open-source LLMs, where you would have access to the complete dataset used for training. Besides the fact that nobody who had used a really big dataset wants to show it, due to possible legal problems, having access to the original dataset would not be helpful for most people, because they would not be able to use it to make an LLM, due to its huge size and due to the vast resources required for pre-training.

On the other hand, continuing training from a BASE model, which is greatly compressed in comparison with the original dataset, is feasible for many.