I don't think most people suggest vim as a replacement for an IDE. In fact, personally I use vim bindings in my IDE because I think I think it's an efficient way to edit text, whereas the IDE provides things vim is not good at (e.g., navigating large code bases by easily jumping to definitions, doing automated refactoring, etc.).

However, there's also times when I don't have the luxury of using an IDE or when I just need to make quick edits to a single file. In these circumstances, I can just fire up vim and quickly do what I need to do because vim is ubiquitous and editing with it is efficient.