To me it says that they _do_ train global models with customer data, but they are trying to ensure no data leakage (which will be hard, but maybe not impossible, if they are training with it).
The caveats are for “local” models, where you would want the model to be able to answer questions about discussions in the workspace.
It makes me wonder how they handle “private” chats, can they leak across a workspace?
Presumably they are trying to train a generic language model which has very low recall for facts in the training data, then using RAG across the chats that the logged on user can see to provide local content.