I hate to throw gasoline on the fire, but there are also differences in clamp design and quality. Some systems are more prone to slippage, or have less micro-adjust capability. Others clamp in a way that damage saddle rails, especially lighter tubular on non-steel rails.
There are also differences in failure modes. For example some posts are designed to bend at loads lower than where they'd snap, while others will snap before they bend. Likewise with clamps where some may lose control of the tilt while still keeping the saddle in place, while others can lose the saddle entirely. While nobody wants a failure, or even to think about them, good design factors the risks and provides for better failure modes if possible.
So while weight and cosmetics may drive the process at the higher end, failsafe engineering may be the difference between lower and mid-range posts.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.