The insert key is located in incredibly non-standard and inconvenient positions on many keyboards. For instance, right now I'd have to hold down a special mode-shift key, shift, and then find the insert key, which I don't believe I have ever typed on purpose in my life - it basically exists as a huge PITA, like the Caps-Lock key, that occasionally puts me into overwrite mode or does other things I didn't intend when I fat-finger it.