I wouldn't necessarily say it reduces cognitive load, but I can get things done more quickly.
- I can delete a whole line/function/paragraph with one command from anywhere in the viewport.
- I can bring a variable name from anywhere in the viewport to anywhere else with one command, and if the name is hard to type quickly or doesn't autocomplete well (perhaps because it is similar to other names in the file) that is a large boost in speed.
- I can add whitespace around function arguments, or empty lines above/below any given line without having to move my cursor there first.
- I can delete a whole line/function/paragraph with one command from anywhere in the viewport.
- I can bring a variable name from anywhere in the viewport to anywhere else with one command, and if the name is hard to type quickly or doesn't autocomplete well (perhaps because it is similar to other names in the file) that is a large boost in speed.
- I can add whitespace around function arguments, or empty lines above/below any given line without having to move my cursor there first.
- etc.