When ur team plant the spike, u guys play inside the bombsite with ur team, using your smokes to difficult the retake, or usually just leaves the bombsite to play line-ups and leave your team?
Here is the play. If you have the choice you should always go for team over lineups. Often using a molly on the choke point they flood through is better for winning rounds, alternatively use them to clear corners like cubby B bind etc.
Lineups are situational but here are a few times i would use them.
A) Free site from a fake. The additional delay from their rotation makes lineups really strong here but you need your team to play with you.
B) Eco rounds, often you need something special to win these so using your lineups can really help turn a loss into a thrifty
C) If you are down players
Really any situation where they can't reach the bomb till your lineups are effective or if you need to clutch a 'lost' round
hope this helps
honestly just play site on maps like haven cus only one entrance your snakebite and smoke is very powerful on a and c
other maps is situational depending if you have ult or not lineups are sometimes a bit unreliable so playing site denying entrance to defenders with your molly and smoke is usually really good