The bottom line is, if you are sure you'll never be coding in the console environment, vi is unnecessary, as these days a good text editor can do everything and beyond.
Keep in mind, vi was started in 1976.
However, many jobs do require console programming, and it's quite handy for quick changes at that...or browsing a network machine via SSH... A GUI in this case would likely not be available, or just too much of a bother to setup. ...and it's good practice if you're going to ever get involved with *nix.
With that being said, vi is good to know, but for your web programming, it is unnecessary and would require quite a bit of overhead to learn (or more importantly, remember all the key combinations).