Mostly cause everyone and their grandma worshipped that scene like it was a second religion.
Galuf's death was what helped make him a great character. He stood bravely against the odds, and managed to hold off Exdeath. In essence, he alone saved the group from death. Of course, such an action cost him his life, and it was an emotional scene.
UNLIKE Aeris, thankfully, all the effort used on him doesn't go to waste, but transfers onto his replacement, which was VERY generous. I liked FFV a lot, because it did a lot of things right. Keep playing the game, it gets a bit more intense.