Yes, Ashton, he's the guy with the dragons
And no, I didn't fill it completely, as that is nearly impossible.. but I did fill a lot of it. And it's not pointless. Not at all.
If you get at least 30% of all the Sound FXs, then Galaxy mode is unlocked. And if you get at least 50% of all the Sound FXs, then Universe mode is unlocked. Normally you play on Earth mode. However, if you have unlocked at least Galaxy mode, then you will have a new option when starting a new game - namely to select the battle mode: Earth mode (normal and easiest), Galaxy mode and Universe mode (if you unlocked that too).
In Galaxy mode, all enemies receive a big bonus to their HP and Strength.. meaning that they will be doing A LOT more damage to you and take longer to kill. The game simply gets a lot more difficult.
In Universe mode, all enemies receive the HP and Strength bonus of Galaxy mode, and also get much higher defense and higher Artificial Intelligence (ie, they get smarter).
Galaxy mode can be a tough nut to crack, and Universe mode can be insanely hard to beat. If you want a challenge, try to beat the game on Universe mode without using the Bloody Armor trick I mentioned somewhere up there. If you are playing on Universe mode, I can assure you that Star Ocean 2 becomes the single toughest RPG game ever made. Even the first boss can wipe you out in like 2 hits on Universe mode. In Universe mode, simple normal random battles can be devastating if you're not careful and have good equipment. Of course, Galaxy mode and Universe mode are only for the hardcore SO2 players, and you most likely need more than 1 file to get enough Sound FX to unlock them (all files you have add up on the Sound FX screen).
So it's not pointless to get them.. and I haven't got all, but more than enough to unlock Universe mode.