The "FRFR" option makes most sense for those of us whose bass sound is covered FoH by the PA rather than the bass rig.
Think about it.
When was the last time you saw a bass cab mic'd up? And if you did would you know 100% that it was the mic'd cab you were hearing or if it was just for show. Then if the bassist was using multiple cabs of different designs, in order to reproduce the sound FoH each different cab would require a mic on it.
And using a DI, anything taken from the amp will be before the power amp section, and usually the sound engineer will request a pre-EQ feed, so at best only the pre-amp section of the amp is going to affect the FoH sound, and most of the time it's probably only the input circuitry. So all those impressive looking all-valve heads are contributing almost nothing to the FoH bass sound.
So why waste time an money agonising over bass amps and cabs when most of the time only you are going to get the benefit, and on anything other than the smallest stages only if you are stood directly in front of them? If most of what you are hearing is coming from the monitors or in-ears which are fed from the same source as the FoH what is the point of a big and heavy bass rig?