Consider that if you are building a house, you will need a foundation. The higher you want to build, the broader your foundation will need to be. When you are learning guitar, or any musical instrument, music theory is your foundation. It enables you to build your instrumental skills, and without it you will be on some shaky ground.
That doesn’t mean you need to do it right away, but realize you can only get so far without it. If you just want to fool around, make some noise, and have fun with the guitar, you won’t need much in the way of theory.
You can learn some songs, sure. But to get good at the guitar, and make steady progress with your music, it’s wise (and not very difficult) to at least learn the basics of music theory using your guitar.
Can I learn music theory using guitar?
The guitar is an ideal instrument to learn music theory because it can play rhythm, chords and scales. Most accomplished guitar players have a solid grasp of music theory topics which allows them to understand and play complex music, learn new songs easily, and communicate with other musicians about the music when playing in a group.
The guitar is such a useful tool for learning music theory that there are many books, videos, teachers, and courses that deal specifically with music theory for guitar. It even has its own name: “Fingerboard Theory.”