Replace XB3 gateway with Arris SCG2482AC gateway

I have read most of the Xfinity articules, but I am still a little confused.   I want to replace my Xfinity XB3 gateway (with phone) and purchase an Arris SCG2482AC gateway (with phone).    I have verified all the specs and it is listed as a compatable replacement.  The Xfiniry articles state that I may lose "xFi WiFi management platform or usage of home based WiFi extras".  What does that mean?  What will I lose, if anything in simple terms.   Any help would be great!