Omen is one of the few agents in Valorant whose abilities do not deal out any damage. His skills are strictly used for traveling across the map and obstructing/tampering with the view of the opponents. Some other “smoke” agents also have a smoke cloud, similar to Omen, but theirs will also deal damage like Viper’s abilities.  Another one of Omen’s weaknesses is that when he uses his Ult ability to teleport, From the Shadows, it makes a loud noise that everyone across the map can hear. So, when he does deploy this ability, the other team will be made aware. As mentioned, you can use the audio to your advantage and mess with the other team. But more inexperienced Omen players may not have the foresight to do so.