well I think it's because the idea behind a Phoenix is that it actually does rise from it's own ashes, it comes back to life. So using a Phoenix Down implies coming back to life. Though, anyone who knows anything, realizes that it's just recovering the person from an unconscious state.

As for why you get a game over? Because no one is there for them to be revived from an unconscious state, so presumably, you would be killed. That's why games where a character gets knocked out and replaced with another character on your team traveling with you make sense, while other games that have entire parties (though you only control like 3) and those three being KO'd = game over make no sense.

In Lost Odyssey, there were 4 immortals. If an immortal was KO'd, in 3 rounds they would recover. But if all of them were KO'd at once, it would be a game over. Funny that they survive a Meteor hitting them almost directly, but can be defeated by a bunch of swords swipes.

THE JACKEL