I found the following link
http://www.hdespot.com/2014/12/01/new-sqlscript-features-in-sap-hana-1-0-sps9/
and there it says "At one time, it was recommended to always use CE Functions over SQL in both SQLScript stored procedures as well as scripted calculation views as they performed better than SQL. This is no longer the case. The recommendation moving forward is to use SQL rather than CE Functions within SQLScript."
Although not what I posted above this is probably what I remembered reading.
Cliff