Because it lowers the center of gravity…

lower bars mean YOU are also lower, which means the overall center of gravity is lower.

 

I think we are talking about two different things. I'm talking about the actual weight distribution of the bike regardless of the handlebars. Pretend there's no handlebars at all and your sitting on the bike just holding it with your feet on the ground and thighs clenched slowly take your legs and lightly rock the bike side to side. With a motorcycle that is top heavy like the the last generation baggers for example it's going to want to fall sideways even with the slightest movement.

Then get on the last generation softail for example and do the exact same thing. You have way more lead way. Much more stable. The weight distribution is lower on the bike and just a more balanced design.

As far as the handlebars that's a different subject. Of course if your racing you want lower handlebars for more control. But if you want comfort especially to take tension off your back and shoulders you want higher bars approximately shoulder high or a little lower. I'm sure we are all different in that department bit that's what I need.

 

This handlebar thing is a good example of 'one size doesn't fit all'.

I had a Road King with stock bars before trading it for the Road Glide. The Harley site shows the Road Glide is about 20 lbs more than the Road King. Additionally, my RG weights about 60 lbs more because I installed a 40 lb tour pak.

Despite physically weighing more than my Road King, the bike 'feels' lighter. I notice it most a slow speeds.. When doing tight U turns or maneuvering in parking lots. I attribute this to the taller bars. I've never ridden a bike with bars this tall. They feel much more comfortable. But others see it differently. It's definitely a personal thing.

 

I found it boring and slow in comparison. Handles nice tho, but not the same rush.