I guess you could also answer that with: because tastes are different. I actually prefer the feel of Lenovo's plastic to metal. I don't remember ever trying to balance a laptop, so not sure what uneven weight distribution would even mean. My x230 does creak a little when I press some point I am never touching while actually using it, only while holding it. On the other hand most keyboards on most laptops don't withstand the pressure I am using when typing.

Apparently I also hold my laptops differently because with the older MBPs the edge at the front hurt my wrist more than working on any other laptop ever had.