I've been watching that for years. I don't swear by it either, depends on the bow, but definitely pay attention to it.
Whether symmetrical or asymmetrical, it should balance pretty well on bow center... unless it's a really odd case... like one limb has a big knot, or really odd character or something. I design my bows so they balance on my middle finger and begin to take note of how it's balancing as the stave is being roughed in... before floor tillering or the long string. If it doesn't balance on my middle finger half decently, I closely inspect, and look for reasons why I may want to work on the heavy limb.
A few days ago, just before I braced a bow for the first time, I held it at my side on my middle finger(bow center) and it tipped forward toward the top limb. It's short and radical and I'd been struggling with this bow for some time, so I double checked my hand placement and tried again... still tipping. I assumed it was just being weird again and braced it anyway. Yep, top limb was too strong. Just a minute or two of scraping made it look better at brace, but that little bit was enough to keep it from balancing in my hand.