I went down the rabbit hole here so let me share what I found… 
Looking at some older community posts, I found that the BI Connector releases page does point to a Customer Agreement page that restricts the use of the BI Connector to just internal and development purposes without an Enterprise license.
Interestingly, MongoDB AI says that you can use it with Community Edition. Looking at the documentation, it does mention that you can use it with self-managed MongoDB, which typically also means Community Edition. I think that this is just technically correct and it’s possible that MongoDB AI has been trained with mostly the technical docs - hence why there is a disclaimer to verify information prior to use.
Lastly, I did find this post with an answer from the product manager for BI Connector, @Alexi_Antonino. @Alexi_Antonino I hope you don’t mind me tagging you here. Would like to seek your help to clarify this further.
References to other similar questions: