Some use the smaller 10" and 8" monitors because they have enough low-end for guitar but more because of (a) weight; (b) wider dispersion pattern on the horn driver.
The RCF and CLR have co-axial high-frequency drivers; better sound from this type of design is one reason why they are supplanting the QSC. However, the QSC (and similar offerings from JBL, EV, Yamaha, etc.) are readily available and not too expensive.
If you're going to use it only for recording, studio monitors are fine but just aren't going to move the kind of air that even a compact PA speaker like the QSC can.
The other FRFR option is to simply plug into a correctly set up, quality PA system, but that's overkill for a simple setup.
Some people prefer to use separate power amps (like the Matrix) and unpowered FRFR cabs. And others still bypass the FRFR solution and use a power amp (again, Matrix, Crown, QSC, what have you) and run directly into a guitar cabinet. In that case you will not want a cab block in the Axe FX II patch chain.