Put simply, scales are like a musical ladder. It's a series of notes that go up or down in a specific order.
Musicians use these for everything - songs are built using scales, both in the chords and in the melodies. Whatever piece of music you are listening to, there is a scale behind the scenes, holding everything together. It's like the skeleton of music. If you know what scale is being used, that means you can improvise over the music yourself, as well!
The first scales we will learn (Major, Minor, and Pentatonic) are all extremely prevalent in music today. Learning just these 3 scale shapes will be enough to set you on the path to understanding how most songs are constructed, let you begin to play along with them, and eventually write your own pieces of music, as well.
For that reason, scales are NON-OPTIONAL.
You can always learn how to play songs without understanding a thing about music theory, but if you want to do anything else with the instrument, you must learn your scales.
I recommend you start on them right away. They will help you no matter what your guitar goals are, and there's no such thing as being too comfortable with them. Once you understand how vast the applications are for scales, you'll be glad you did!