Oh, sure, I agree. Unless you're using a giant scale plane as a trainer. (uncommon, but not unheard of).

Frankly, beginners often break props, some beginners break a number of them. If the props aren't lasting long, or are getting nicked up (which changes the balance), then there are other things to worry about. I suspect most people never bother to balance anything.

However, if you're getting a lot of vibration, or if you change props (maybe after breaking one), and the plane seems to vibrate more than it did, it's worth looking in to.

And yes, the info on balancing in both directions is more than a beginner might "need to know", but I always think that it's better to know and not worry about than to not know because no one bothered to mention it. (besides, sometimes I just like typing. Just kidding).

Oh, also, not often, but once in a while you'll get a defective prop with the hole drilled slightly off center. Doing a quick balance check, even if you don't do anything to alter the balance, can be useful to avoid such things. But defective props are rare.