Smoke Bomb only effects the screen making it difficult to see surrounding for everyone, however I have found two possible uses:

Gravitational Shot: If a player shoots a Gravitational Shot within the Smoke Bomb it will be complete hidden, however you can still hear it.

Optical Cloak: If a player enters the Smoke Bomb area while Optical Cloak is in effect, they will be complete invisible to all players. (But using medkits/anti-alinement/reviving other players will show a screen for a few sec