> Not only is [ always in the same spot
Only if it's the same keyboard layout. For instance, on the US layout, [ is immediately to the right of P, while on the ABNT-2 layout, it's two keys to the right of P. Meanwhile, ESC is on the same place (top left of the keyboard) in both.
Not only is [ always in the same spot, but you don't have to move your fingers off the normal keys or stretch. I was fortunate that a friend told me about that early on, otherwise I couldn't have handled VI, the stretching is so inconvenient (especially so on those old IBM PS/2 keyboards with cubic keys).