From my experiences, reading music or theory can be a blessing or it can be a hindrance. Music is ear dominated and playing by ear is the best way. It's really up to you. Do you need it? I read music and I can play it in my head while reading and I also know theory. I need them because I'm hearing impaired. I want to enjoy my guitar and I'm doing it.
There is an advantage with reading music or theory and that's to communicate with the members what you want to do.
"Hey Joe, play a D after this A and jump to E."