Upgrading Service Application databases from SharePoint 2013 to 2016

Hello,

Is there actually a benefit to using/upgrading the SA databases that currently exist in our SP 2013 environment when we configure SP 2016?  Why not just create the SAs and databases from scratch when configuring SP 2016?  Looking for pros and cons.

What data is kept in SA databases?  Just config data?

FYI - These are the SAs we are using in SP 2013.  BDC, SSRS, PowerPivot, Managed Metadata, Secure Store, and Search.  

Please advise.

Trish