The timing to get the smoke out on the detonator guy is very tight and may be impossible on occasion if his RNG reaction is fast enough. Smoke before smashing the door then smoking again to enter the room can alleviate this.

Getting that falling shot through the window only saves about 1 second compared to clearing the room on the way up.

Smoke during the Granny run was for safety. Sometimes the snipers will notice you from off screen, which is usually a death because HP is so low.