There is absolutely no problem whatsoever with looking at your fingers while you play. I do not understand why anybody ever even brings this up. There are no awards for being able to play blindfolded and there are no fines for looking. Showmanship and putting on a good show is a thing all on its own, but looking at your fingers is perfectly fine. If you'd like an example, there's a rather unknown bass player called Jaco that played fretless, he looked at his fingers all the time!
Music, the way I do it, is a team sport. Playing church services, I'm always working with different players and singers. While there's nothing wrong with a glance here and there, one of the things I good at is working
with the other folks on stage, and the vibe in the room. I practice at home to where I know the material cold - chord structure, etc. The part I actually play when I get there, though, depends on what else is going on around me. Yes, part of what I need to do my job well I can hear, but a lot of cues come in visually. If I'm not well rehearsed, I'll be looking at my fingers, and miss visual cues. I don't play without looking at my fingers to show off, I do it so I can (with others) play better music.
I also regularly play on very dark stages - the singers up front get the light, us instrumentalists at the back of the stage are pretty much shrouded in darkness. If you can't play without looking at your fingers, at times you just won't be able to play. One weekend, for part of the service, the band was supplying the "sound track" to a movie. There was no light for the band, other than what spilled off the screen. The movie had a lot of black parts - I had to play in total darkness throughout much of that. I could have asked for a light, but it would have spoiled the vibe of the movie. I'm glad I knew what I was playing, and didn't need to see my fingers for that.
In that past I've played in bands where we would sometimes turn off the lights while we rehearsed. yes, it sounds odd, but it helps you know what you do and don't
know. While playing in that band, a couple of times at a club, we lost lighting, and without a hitch, we finished the song. The crowd
loved it - the applause you get when you can pull that off - totally worth it.