I use it as a marker not a focus.
If a team has poor HR power, it's unlikely they will win enough to make the post season no matter what else they do. History shows that.
Now, the opposite (a team with exceptional HR power making the post season) isn't necessarily true either.
If you look at a team and it appears they have good team HR power, at least for me, means that team passes a gate. Then I look at other factors behind that such as other offensive capabilities, pitching, defense, etc.
Excluding teams who don't have good team HR power sometimes means you miss a team that will ultimately make the post season. But it doesn't happen often.
It's nothing more than a marker but it is a good one.
Ignoring it is equivalent to saying winning in football with defense and the kicking game alone wins games about 5% of the time therefore I'm going to build my team around the kicking game and defense and not concern myself with great running backs, QB's or receivers. Just because you can do it that way and it does work sometimes, doesn't mean it's the way you should do it.