Fire is the cheapest way to make a piece of a map unusable without looking at it. A molotov lineup is not about damage — it is about taking a corner, a plant spot or an approach off the table for seven seconds.
They are two grenades that do close to the same job for different teams at different prices. The Terrorist molotov is cheaper; the Counter-Terrorist incendiary costs more and ignites into its full spread slightly faster and slightly wider, which matters when you are throwing it as a reaction rather than as part of a plan.
Both break on impact with the ground rather than bouncing, which is why fire lineups are usually shorter and flatter than smoke lineups — you are aiming at a surface, not lobbing over an obstacle. A molotov that clips a railing on the way in spreads from the railing, not from where you wanted it.
Chip damage is a side effect, not the point. Standing in fire hurts, but anyone competent leaves it immediately; if you are counting on the damage you have already misunderstood the throw.
A smoke thrown a second late still blocks vision. A molotov thrown a second late burns out a second late, and if your team arrives during the last flicker they walk into a player who has already repositioned. Fire lineups are the ones where the air time listed on the lineup page is most worth reading, and the ones most worth practising as part of a sequence rather than in isolation.
The most under-used fire lineups are the post-plant ones. A molotov onto the bomb from a position the retaking team cannot see you in buys the whole seven seconds back, and does it without you having to win a duel. If your map has one from a common post-plant hiding spot, it is worth more than a second site-execute molotov you will throw once a half.
Notice what is not on that list: fire thrown speculatively at a site on the off-chance somebody is standing in it. That is $400 and a grenade slot spent on a guess.
Because a molotov breaks on the first thing it touches, the useful fire lineups are frequently the ones that get the grenade over a wall and down onto ground you cannot see. Those are exactly the throws that are impossible to eyeball, because there is no visual feedback until it is too late — which is what makes a written lineup worth having. They are also the ones most sensitive to your standing position, since a small angular error at the throw becomes a large one by the time the grenade clears the wall.