The argument against "reading" goes like this:
"Guitar players have to know how to improvise, to go with the flow, and be creative. Trying to analyse and write down the complicated combination of notes most guitar players play is a waste of time and effort. Just learn the chords, memorize typical chord progressions (the usual way chords go together), learn how to strum in different tempos, and go from there."
This argument describes the way most beginners learn the guitar: they learn chords and simple strum patterns, and don't really have to know what notes they are playing. It makes a lot of sense.
But it can also be limiting for beginners. You will probably see the guitar as a chording machine.
But it can be so much more!
Perhaps more important, you will have to rely completely on memory for anything other than bare bones chording.
For example, let's say your teacher, band leader, or fellow band member asks you to play a bit of melody. Imagine your group is playing the Christmas song "Joy to the World" and they want you to take the lead for one verse.
Yes, you can wing it, play "by ear", figure it out and memorize it, and chances are you will remember it. But wouldn't it be good to have some help... "Oh yeah, I see I play a G there and it ends E-D-C."
...to be continued.
There'a an easy way to learn how to read traditional notation. Start with basic scales and simple songs for the guitar. Before you know it, you'll have a pretty good idea of what you're doing.