http://i.imgur.com/pi7qjEb.png should help you find a specific post
Short question, long answer and opinions will probably differ.
Well replacing ::B:: with ::LB:: will increase the damage that attack will do on the enemy camp.
This is interesting if
a) that attack is part of a block, where time is an issue and
b) if it allows you to defeat the camp using 1 wave, since then you won't have to wait for your general to recover (some players have a lot of generals and rather let a general recover then loose more expensive troops)