Keeping a pad of paper at your computer is one of those underrated things. You'd think the computer can record information just like the paper, and it can, but psychology is weird.

Agreed. Grabbing a pen and a post-it is faster for me than opening a text document, and a pad of paper allows me to format and diagram things freely.

The post-its can be sorted, stacked, moved, stuck to pertinent notebook pages, altered, and ultimately recycled when they are no longer relevant. It's much freer than a document on a phone or computer, where it can still be a pain to move information from one domain to another.