I may try to take this one... LTL, correct me if I'm wrong, I'm a rookie fan as well...
An advantage to changing your line last can be great. Say that I'm the coach of the home team, and LTL is the coach of the away team.
LTL throws three very powerful shooters who are slower skaters, an offensive defensemen, who tends to jump up on the play more often than not, and a defensemen who is a hard hitter.
Seeing this, as the home team, I can throw over one of two lines.
Choice A) Three really fast forwards who have good skating/handling, to try to score the game winning goal, with two defensemen. Once the forwards clear past LTL's forwards, it's almost home free, with a 3 on 2 rush.
Choice

Throw out my checking line, and let them bash the other team to hell.
Basically, it means that I can throw out any counter I have to your previous move, because I have the last move.
Hope I helped, and that it's correct!