SFP, FFP...
If you are shooting with another person, it's very useful to be using the same system for communication purposes. This is why the FFP is so popular with the gaming bunch and those that shoot at bad guys for a living. Their reticle reads true at all zoom levels so they are able to communicate misses or get the shooter on a target easily and accurately.
The SFP is just as relevant as it ever was but if you are communicating with a shooter using a FFP scope, you may need to zoom to true your own reticle. If it's also an MOA scope and they are using a MIL scope, the situation is further complicated in needing to convert MOA to MIL and MIL to MOA.
You can easily communicate effectively without any conversions by just using target size as the unit. You observe your buddy miss high right. You call out "MISS, 2:30, half the target." He knows in his view finder what sort of correction he needs to make.