I use one finger when typing "loop", because it doesn't make sense to do otherwise given how the respective keys are on QWERTY. That just means the word "loop" sucks.

Regarding parentheses/brackets, I said "separate fingers", not "separate hands". I do use separate fingers for parentheses/brackets.

The numpad is a weird thing. When I've (rarely) needed it for sustained number capturing, I do typically stick to one finger because it's easy to get lost with multiple. Not sure why. It could just be lack of practice with the numpad.