It's harder to build your own note-taking system based on existing web features than to use an app that does it. Even just programmers, and we're talking about

It's harder to build your own note-taking system based on existing web features than to use an app that does it. Even just programmers, and we're talking about everybody. For every human who can and would do the former, there are perhaps millions who can and would do the latter. That's a pretty big difference, to put it lightly.