I fully support what TheJamsh has written, if there was one area that UE4 could benefit from improving more than any other - IMO it’s here. Only the most basic of games don’t require client-side prediction or can work with CMC in it’s current state and it’s incredibly limiting.
As for CMC in general, it’s a behemoth and a stone-wall to most people who require prediction with out-of-the-ordinary gameplay. Even studying how it does things for your own purposes is a daunting task, it really is Alice’s rabbit hole.