I liked WordPad because it was comfortably simple, did more than Notepad, but didn't have way more than I needed for personal use. It's similar to why I like Apple Notes (even though TextEdit is closer to WordPad). Most of the time, I don't need pages, margins, footers, a bunch of fancy formatting, but the ability to make text bold or italic, add hyperlinks, and maybe change the color or font. In which case I want all the doodads related to those unused features out of the way.
I like WordPad because when I collect screenshots and quick notes about what's of them, it's fast and doesn't get in the way: Alt+PrintScreen, Alt+Tab to WordPad, Control+V, type some text, Alt+Tab again to go back to the application you're screenshootting and you can keep going.
Control+S at the end and you have a RTF that can be read everywhere.
