Triads are essential to being a well-rounded guitar player. If you have any desire to learn how to create your own guitar solos, relying on scales is not going to cut it. In fact, when people ask the question "How do I sound like I'm not just playing scales when I solo?" the answer is always the same: learn triads. Triads are chords, but they can be used as pivot points to allow you to identify particular chord tones over various progressions in order to amplify what makes each chord so special.