You can only have so many keys under your other fingers, and the more you add, the more movement will be required of your hand.
Downshifting, particularly into first as you're coming to a stop sign, it'll save a fair amount of wear on the synchros. Or if you have a car with worn synchros, it'll help ensure a quicker, smoother downshift in general. A 5-3 downshift on an offramp usually benefits, for instance.
[0] Given the substantial liberties they took in general, your skepticism might be justified.
But maybe you'd be more efficient with a chording setup...
Not to be confused with reed organs, which usually just have one big pedal that operates the bellows. Though sometimes they also have levers you can push to the side with your knee.
And away you go. As you get more efficient at vim use you might find you want to turn that off again.
(and also without the colon in your vimrc file if you want it to stick)
:set ttymouse=sgr also makes it a lot smoother.