Question regaurding replication

I am in the process of trying to better understand all of ue4s replication set up and all that… I have purchased someones asset from ue4 market and i was curious why something was done a certain way… attached are 2 screenshots …

ALS_Aiming Event
I see he called it on the server… then the server did the multicast to set a variable.
I get that much.
I see the variable is not replciated but im assuming doing this multicast event on the server sets the variable for everyone. On this character.

In another section I see Looking Rotation variable…
THis one is replicated… and i see a server function is called to set it.
To my untrained eyes it feels like both do the exact same thing
Do they do the same thing for changing a variable for everyone connected to the game for that character?
If so, why did he choose to do it 2 different ways?
if not … what am i not understanding?

  1. replicate server only, updates only server about the change,
  2. sometimes it not about the replication, it’s more about who has the authority of changing a variable

I think for aiming he choose multicast because of fastness.

https://forums.unrealengine.com/development-discussion/blueprint-visual-scripting/1397002-replicating-transform-from-client-to-server-without-rpc?p=1397369#post1397369