Currently the lowest thumb button is pretty far from the highest thumb button. This introduces a fairly significant finger travel distance when moving from thumb top to thumb bottom. That affects both the speed at which the button can be pressed as well as the strain introduced on the thumb.
Currently the lowest thumb button is pretty far from the highest thumb button. This introduces a fairly significant finger travel distance when moving from thumb top to thumb bottom. That affects both the speed at which the button can be pressed as well as the strain introduced on the thumb.