A great use would be to enable one to have conversations with Pascal or Leibnitz, etc.
For instance, I published online the complete text of the Mémoires de Saint-Simon (written in 1745-1755, but describing the second part of the reign of Louis XIV and the Régence, 1695-1721).
Saint-Simon was described by his contemporaries to be one of the greats conversationalists of his time. It would be so cool to chat with him.