If you want to do multiple charges, dbl-lft click would be much easier to execute.

It's possible to get your cav out immediately after a successful charge, w/o losing more than 1-2 men, and repeatedly execute a charge again. Terrain wise, it's always easier to charge downhill.

My feel is that Cav's primary adv. is in mobility and charge bonus. So it's always more useful to get them to do repeated charges, instead of melee.