It is the only editing system that makes sense to me. That's because modal editing means fewer modifier-key combinations are needed, and no mouse is needed. Compare with.. any other editor, where the only thing that might save you from RSI is enabling sticky keys, and even then, if it isn't emacs you still have to heavily use a mouse.
For a great number of tasks, being a vim or emacs pro means doing things faster than any other editor could do them (except, maybe refactoring). And vim will save you from from more RSI than emacs by having fewer modifier key combinations.
Every IDE needs a vi mode.
Wherever I can I use tmux+cscope+ctags+vim+shell as my IDE. One tmux session per-project, nested in one big tmux session for all projects. Window #0 has a cscope with a an $EDITOR wrapper that opens new edits in new, appropriately titled tmux windows and returns control to cscope. Windows #1 through #4 are for a shell. The rest are for editing files opened via cscope. It's a dream for C/C++, even Java. cscope needs support for more languages, that's true, certainly, but this gets me quite far.
To me, using "no mouse is needed" as a positive is like building a car that uses extra pedals to steer and saying "no steering wheel is needed". Mice are great. I want to use mice.
Mice have their place. But they have issues with precision, RSI, and force the need to move the hands to/from home row.
And if you use a laptop as a primary work tool, being able to avoid the touchpad (or trackpoint for those ThinkPad users out there) is a huge advantage.
http://www.edkeyes.org/blog/050728.html
Somewhat ironically, the inventor of the computer mouse, Douglas Engelbart, is still a bit critical of modern graphical user interfaces compared to the fuller vocabulary of, say, the command line. "Here's the language they're proposing: You point to something and grunt," he says.
I love vim, but I do feel that my reliance on its awesomeness has been reduced quite a bit since I switched to using a Kinesis Advantage keyboard. For one, the cursor keys don't require me to move my hands at all, so I no longer use hjkl to navigate. I also have quick easy access to all modifier keys and I use a foot pedal too. I do still use vim, but I've essentially mapped all of the fancier features to pedal+main keybaord single button shortcuts - Kinesis Advantage macros also means it works fine in a stock vim.
Yes, yes, when I don't have my keyboard, I still use the normal vim features, but I try to use the keyboard as much as possible for anti-RSI purposes anyway, so its not a big deal.
Yes, you can use a lot of other editors without a mouse. The advantage of learning vim/vim mode is that you can be proficient with them without having to learn their editing keybindings. Vim mode acts as a common interface. I even use those keybindings in Chrome with cVim.
This is also not exclusive to Vim. I don't use any plugins and I have a lot of common key bindings (especially for text editing) I can use on every text editor field on my Mac (which are pretty similar on Windows). Heck I even have Emacs keybindings on OS level on macOS nearly everywhere (without installing plugins): http://jblevins.org/log/kbd
So Vim is an addition where as my key bindings work everywhere except when I go to the console where I had to learn some nano specific key bindings but which match a lot with the basic text editing keybindings from Emacs mentioned above.
For a great number of tasks, being a vim or emacs pro means doing things faster than any other editor could do them (except, maybe refactoring). And vim will save you from from more RSI than emacs by having fewer modifier key combinations.
Every IDE needs a vi mode.
Wherever I can I use tmux+cscope+ctags+vim+shell as my IDE. One tmux session per-project, nested in one big tmux session for all projects. Window #0 has a cscope with a an $EDITOR wrapper that opens new edits in new, appropriately titled tmux windows and returns control to cscope. Windows #1 through #4 are for a shell. The rest are for editing files opened via cscope. It's a dream for C/C++, even Java. cscope needs support for more languages, that's true, certainly, but this gets me quite far.