Conventional music notation is a complete self contained language. It allow music to be written down and communicated without ever being played. Many rock, folk, country etc. guitarists never learn to read music. In fact many well known guitarists do not read music. This is unfortunate not because their music would have been better but because it tends to make beginners think that learning basic music notation is not worth the effort.
I contend that there are at least four major reason why learning music notation is worthwhile.
1. It means that you can take any piece of music from a songbook or sheet and play it without ever having heard it.
2. It means that you can keep a permanent record of any of your compositions.
3. It means that you can convey musical ideas and compositions to other musicians without having to play them.
4. Finally, the way in which music is written often helps explain the theory and principles behind chords, scales, melody, harmony and rhythm.
On this web site I have a complete course in music theory. Learning this is not a pre-requisite to playing the guitar but it is if you want to become a 'Musician" and not just a guitar player.
Other methods of conveying information are very helpful and can be used by themselves or alongside basic notation. Chord diagrams, fingering patterns, photographs, videos, charts etc. are useful. the choice to learn basic music notation is up to you.
Basic notation is not difficult to understand but like any language it takes time and practice to become fluent. Sight-reading is not something you can pick up overnight but the basic concepts are relatively easy. Review the section on Notation.
Guitarists and other stringed instruments have another system in addition to music notation called Guitar Tablature. Although Tablature is handy it does not convey precise information about timing so it requires hearing the music or using it in conjunction with notation.