Power chords are not really chords. No, really. Hear me out.
Chords are 3 notes or more, whereas power chords only have 2 different notes. A correct name would be “power intervals” because they only contain two different notes. Usually, power chords are composed of the root, a perfect 5th interval, and the root note doubled at a higher pitch (called an octave). Basically, they are just like playing perfect 5th intervals and doubling up a note or two.
Power chords are easy to play just about anywhere on the neck but lend very little harmonic texture to a song. They do not have a major or minor third interval. A chord needs this interval in order to make it a major or minor chord.
If you’re playing a song with a lot of distortion, strumming a full chord might create too much dissonance. Plus if you have a fast chord change, it’s often easier to use power chords for the really fast part.
No Substitute For Learning The Real Thing
A lot of players get caught in the power chord trap. They learn how to play power chords but fail to learn the real chords. This is a major mistake. Just because you can play a C power chord does not mean you know a C chord. As we said before, they aren’t really chords anyway.
Learning chords are one of the most important things a guitar player can do. It does not matter what style of music you are interested in, you cannot avoid learning your chords! Failing to learn them will mean that you will fail as a guitarist in the long run