Honestly, that strat went out the window once we got the ^. No need to waste time using the Greek keyboard exploit, expecially since the top runner was found to be using macros to emulate anyway.
^ needs 2 keypresses, shift+6. You might as well just type "up." Also note that the speedrunner here used a capital i, also an excess keypress, except for the fact that you're allowed to be holding a key down before you start. Just a bit of showing off, I guess.
No, unless you're using the 5 finger style it's proven a non-dominant stroke is negligible since 6 is in the C1 vector and shift is in in the A4 vector.