Guitar power chords in popular music serve a similar role as their non-power chord counterparts from a music theory perspective. For example, in the key of A, a chord progression of A5 → F#5 → E5 would be analyzed in Hooktheory as I → vi → V. This analysis isn’t 100% accurate, since power chords technically have no quality (major vs. minor), however it serves to preserve the function of the chords.
Of course, if you’re writing a song with chords that will eventually be played as power chords, you’re probably going to want to hear Hookpad play it that way. Power chords are an extremely important part of popular music spanning many different genres and styles. Part of our motivation for introducing the “mix” tool, was to allow you guys to hear the songs you write in Hookpad in a style that is closer to the way it will eventually be played on real instruments.
We recognize that some version of a distorted electric guitar playing power chords is an essential addition to the mix tool. Getting this right is a little tricky, so it wasn’t included in the initial release, but we definitely plan to release new instruments and voicing as we create them, and having a power chords option is high on the list.