If you want to multi mic - note this is NOT stereo, then it's a choice that will cost you. Technically it's possible the sound you like is a result of phase cancellation, which strictly speaking is a happy mistake that works for you, with these instruments and voices in your space. It's very unusual to record voices this way, and of course two mics on one mouth is mono. The reflections they capture give an illusion of stereo, and if they move their heads while singing the image moves, and in headphones, can sound weird enough for some people to feel like vomitting. I think most of us would record all this stuff separately and then sort out the result in the mix. Mic combiners are a blunt tool.
If it works for you, great. It's creating for you, a strange individual technique we'd not use, but one that could be a character sound for your music. Lots of people record unusually, and that's fine. It rarely translates to general recording skills. My friend is a drummer, and he always records his jazz drum kit in his kitchen, with one mic, and it sounds great. It wouldn't work in my studio and it wouldn't work, I think, if he bought a new kit. It's a happy accident.