Your point is indisputable. Fortunately, it's not inconsistent with my own:
>> [Optimization is sometimes harmful.]
Optimization pays the greatest dividends to tasks which:
(1) could be brief,
(2) but are quite long and
(3) frequently necessary.
As to vim: On (1), brevity, Vim is powerfully so.
On (2), length, I don't recall any of my meta editing tasks involving "100 keystrokes and a mouse movement." Customizable shortcuts can trim down the outliers.
On (3), frequency, this surely depends on the person and task. I rarely delete every third occurrence of x between the seventh and ninth y... but if I used vim, I would make a point to.
So, I would turn to vim if there were several meta-editing tasks I routinely performed, each requiring a large number of keystrokes, each of which vim could reduce.
And hey, maybe this is the case. I'd love to see a plugin that analyzed my editing style and made suggestions to make me more efficient.
But originally I was just noting that efficiency and optimization are messy.