I agree with what's posted above. I too, prefer an "amp in the room" vibe. In it's purest form, a power amp and cab is the way to go.
But I've also played around, fairly successfully, with getting decent amp in the room vibe from a full range PA monitor.
Do a little research on the frequency response of the real speakers your IR is simulating. Then bring your High and Low Cuts on the Cab block down to those parameters. Fiddle with the 12 and 6 db cut also. IMO, there is no need for extra high end on the FRFR when there is so much ability to dial back any frequencies you want to. There is simply no reason to put frequencies through your monitor that a real guitar cab cannot (or isn't expected to) generate. IMO, of course... If you're lazy like me, just start with your low parameter at 150 and high at 4500. Then adjust to taste. These adjustments will be necessary depending on the amp and IR you're using.
I like to do the above to dial out the hi-fi vibe of the tone anyway. Doing this loses some low end punch that can be compensated for (in a very realistic way) by using the proximity on the microphone and moving it close to the speaker. Adjusting the proximity frequency dials this in even more.
Since I've started doing this, the in-room experience for me has improved considerably. My guitar tone blends much better with my band at practice too.
Most here know lots more than I do about all of this stuff. But this has worked for me. But I also have a 2x12 cab and a power amp, just in case