I've found that when teaching people Git, the most important thing is that they understand the state of their DAG, since that is at the core of everything we do

I've found that when teaching people Git, the most important thing is that they understand the state of their DAG, since that is at the core of everything we do in Git. A confusing DAG full of unnecessary merge commits is much worse for a beginner than exposing them to rebase. Git lends itself as a development tool as well as a version tracker, and rebase is an important part of that for both beginners and experts.