If i am not mistaken, you would need to create topic on the top of dataset any way for user to be able to ask Q&A. Q would not know where to generate answers from otherwise.
you may see Q&A tool bar but unless topic is there you wont be able to link it to the related dataset to ask Question.
On the other hand, when it comes to Embedding you would also need to explicitly embed Q bar with the embedding.
We have Q&A enabled pricing for readers.
So when We share dashboard with Q&A to readers then they are able to ask questions from console without any need for topic creation.
But Yes, we need this via Embedding which seems currently not supported but would be good to have.