Doesn't that hack allow you to write to arbitrary memory? Being able to write to attacker-controlled memory is a serious problem. That's not what the kill(-1) bug lets you do though.
The attack was a buffer overflow on handling objects in the "saved item" area at the top. By manipulating objects as done in the video, one can set RAM up as needed to construct the "program". Then when the overflow is executed, it jumps to the invalid place in memory, thus executing the code you seeded.
This is also done in Pokemon Yellow with a link cable. The last time I saw this being done, a TAS hacker was able to inject a TCP stack over the link cable, and build an IRC client on top, and chat using the game boy.
And I realize that's not the immediate action that bug has, regarding kill(-1). But I've seen what people thought were innocuous bugs that ended up being "gimmee root" kind of bugs.
