I would say that it is not supported.
This URL,
https://technet.microsoft.com/en-us/library/dn832152.aspx says that CRM 2013 and CRM 2015 are not supported on Outlook 2016.
However, this URL https://support.microsoft.com/en-us/kb/3005163 says that it is supported. But I think is a mistake. This article says that Office 2013 SP1 is supported with CRM 2011 Update Rollup
17 but Office 2016 is supported with CRM 2011 RTM (i.e. no Update Rollups) which is clearly not right.
Although installing it might appear to work as you have found there may well be issues so I think you should assume that it is not supported. Time to upgrade to CRM 2016! (if you can)