As a cowboy chord guitarist BIAB works fine with 3 chord songs. And as an example Dance the night away by the Mavericks only uses 2 - E and B7.
It does have something to do with music education.
Most music is for ordinary people.
By the way, is there an example of using 1 or 2 chords in BIAB? Let me open it up. I can't find it.