I think I heard and read -6 EV with the new 50R
If that is indeed true
then Its a no brainer for a wedding photographer to invest into a dual card EOS-R body and the 50R
That means you can track in the dark and that opens up avenues of creative freedom. A clean sensor at 25K, -6 EV and the world is your oyster. Unlimited possibilities.
And we are almost there now with what we have. The 1Dx2 is a beast in the dark. Speedlights in ETTL in Minus settings or video lights kills it at receptions
so yeah advantages with these features
That spec is using one shot AF, not Servo.