I've always used fairly good quality headphones at home (Shure SRH840), and sometimes I let the sound go via two powered STK 650W aktive speakers.
Also bought Genos speakerset, in fact they sounds really good, and I will say it's great for home use.

When perform gigs, it's usually quite a lot human noise surrounding, and even if output is mixed down from stereo to mono, the crowd would probably not hear any difference.
If you perform as concert performer, full stereo will most likely be more noticeable?