Replicated variables should always be used when changing a state in the game rather than using a Multicast RPC since RPC can and will desync while OnRep variables are reliably replicated.
The only downside to replicated variables is that intermediate changes might be dropped but this is also what makes variables that change often much more lightweight than RPC’s.
Multicast RPC’s should only be used if you are doing an instant action like playing a sound or animation or notification that only matters right when it happened.