This Molotov is used to burn the mid boxes when TTs have smoked off window, to help short/underpass/connector teammates fight for mid. If you're going through vents, you can use this faster lineup instead.
Technique:
Pre-aim and don't move the mouse from this point. Go to the corner, press W, and release before hitting the window. It requires practice as it's intended to be thrown from inside the window smoke.