I email myself all the time. A half dozen times a week at least. Looking at my sent items box now, I did one this weekend when I ran across a neat hike I wanted to do from a Reddit post. I actually have a place I keep stuff like this (a special project in Things) but I didn’t feel like putting it there right then. I wanted to email my wife about it too, and who knows, maybe look into it a bit more first. That’s for future-self to deal with.
In that case, it’s sort of like my email is my TODO list, but it’s more like a “deal with this later” list. That’s distinctly different to me. My TODO list items are specific tasks with context. An email, to me, isn’t a TODO list, it’s a “deal with this soon” list.
Notice I had to look in my sent items box to find that email about the hike, not my inbox. That’s because (probably just hours later) I did what I wanted to do with it (read the article on a larger screen, emailed wife, put on my real TODO list of places I want to go in proper context).