Depends.
In the band I front (on vocals and skinny-string), I never use a music stand. I occasionally forget my words, but it's worth it for the fact that I am free to engage with the audience, not looking down at a piece of paper.
If I am depping on bass, I generally aim to learn my part, but if it's at short notice or very involved, I will sometimes take out the sheet music I have transcribed.
Obviously if it's a sight-reading gig then a music stand is essential, and the issue then is whether to sit or stand. I am generally more comfortable standing than sitting, but this means having the music stand quite high if I want to avoid a painful neck as the gig progresses.
As a gig-goer I hate to see (or indeed not see) a band obscured by a forest of music stands at chest height. IME brass and woodwind players can rarely get away without the music in front of them.