As I understand it it was used (primarily by cavalry) to dig into a unit from the front and then "explode laterally," effectively flanking it from within without having to get around the side. But in the game the wedge just stops when it hits and becomes pretty useless after that. Oh well.
I don't know about that. the effects aren't always spectacular but they certainly disrupt the enemy lines more than a flat fronted charge, important if you're out-maneuvred and have no choice but to stall their line with a frontal charge.
If you want spectacular though, charge teched up Lancers downhill into pretty much any unit and you'll see the enemy formation burst apart. You need to time the change in formation back to tight though.