Sight reading is an important skill that every musician needs. It may be one of your most marketable skills as a musician. In the real world, unless you are a concert musician, you often don’t have a lot of time with a piece of music. Studio musicians, accompanists, church musicians, each one of them need to do a healthy amount of sight reading in their daily jobs.
Like all other musical skills, sight reading is learned. That’s not to say you won’t learn the basics of sight reading by just being a musician, but you likely won’t get proficient at it unless you practice specifically sight reading consistently.