This system doesn't really require emacs. The general idea is to assign keybindings to jump to today's daypage, the previous file, and the next file. Being able to create a daypage that doesn't exist is helpful (but not necessary -- you could create 300 of them with a shell script once a year), and being able to search for things in a folder is also helpful.

You can implement that with your favorite text editor. You could do it with Notepad and AutoHotkey if you were persistent.

Org-mode adds organization, but honestly I benefit from its syntax highlighting and the bragging rights more than anything else. :-)