The number of keystrokes is an interesting number to use because it is only roughly correlated with the time it takes to press the keys. Both 2dd and 2[] are three keys, yet the latter can be typed much faster than the former as it is spread over both sides of the keyboard and it doesn’t repeat a key (so you can “roll” your fingers over the [] which is faster than double pressing the d).
In the case of g-shift-I, I’d call it 2.5 keys. Assuming you press g and I with the right hand, the shift key hardly matters in terms of time. Of course, by the same logic, 0i is faster still.
Of course I agree with the main point that keystrokes is not the same as fast to type, 2dd would indeed take me longer than 2[].
For me, though, shift is annoying. The duckduckgo bangs I find a pain and I don't use them (shift+1 is fairly uncomfortable a keystroke compared to one of the symbols available without shift) but a lot of people advertise it as a handy feature. Timing the shift key correctly is something I get wrong more often than other keystrokes, perhaps because it's operated by the pinky (though letters like "p" in operate and "a" in and are also pinky-operated and those work fine for me, idk). For me g-shift-i it's really 3 keys, not 2.5. I'd even go so far as to say that 0i is more like 1.5 than 2, since they're so nicely next to each other. By moving my right ring finger to the 0, my index finger almost automatically falls on the i. Conversely, the g and then shift makes me have to stretch my hand slightly (I find that less comfortable than shifting its position), or if I were to use the right shift, then that would be quite a big movement and stretching back to reach the i (though I rarely use the right shift: my natural hand position (to not have my wrists at an angle without needing to use a split/angled keyboard) has my right pinky in the position of the p rather than the semicolon).
In the case of g-shift-I, I’d call it 2.5 keys. Assuming you press g and I with the right hand, the shift key hardly matters in terms of time. Of course, by the same logic, 0i is faster still.