Don't mind about "Guitar", it could be Bass or anything else. Imagine you have 2 setups:
Guitar -> Pedals (stereo end) -> 2 Amps running -> Mixer
Guitar -> Pedals (mono end) -> 1 Amp running -> Rec Out/Phones -> Split to 2 channel -> Mixer
Let's say (on 1st option) rather than running the delay in stereo, I run it on mono (so it won't have ping-pong delay), but I put chorus and reverb in stereo. On the other option, I pan each channel (on the mixer) hard left and hard right. Would it be any difference? If there is, what's the differences?