>>712802042
It's the same reason people cared about high scores back with arcade games. That was the metric the games gave players to show how good they were at the game. Once home consoles got more popular than arcades, high scores started falling out of favor. So they had to find new ways to compel players to keep replaying games. Zelda had a death counter, so naturally a player would be compelled to attempt no-death runs. Games like Metroid and Castlevania 2 used speed running for different endings as their new incentive. This practice is even more prevalent with modern games all having their built in achievements explicitly telling players what the developers think they should focus on when playing.