I don't need to spout the benefits of the jump serve... everyone loves a good jump serve.
But the glamour of the jump serve often overshadows the effectiveness of the float serve. This can be especially true in younger players. Most younger players are not able to effectively jump serve and are pushed into it before they are ready and before it's even necessary. A well executed float serve is more than effective enough for an ace.
A float serve is a great tool even in the upper levels of the game. A deep float serve allows for the ball to catch more air and thus more movement. In many ways, a good float serve can be harder to pass than many jump serves.

