So there was some initial debate between Activision and Ubisoft about whether Destiny or Watch Dogs had the bigger launch, and given this comes from Ubisoft, I'll take this as confirmation it was Destiny.
https://www.ubisoftgroup.com/comsit..._180216-site_tcm99-239259_tcm99-196733-32.pdf
https://www.ubisoftgroup.com/comsit..._180216-site_tcm99-239259_tcm99-196733-32.pdf