Basically what the title says. I've seen many people who are very good with the op doing this thing. They shoot and then quickly switch to the knife and then back to the op. What benefits does it have?

Is he useful or a niche pick? over or underpowered? Opinions on his kit and balance? I saw a lot of people saying he was op whrn he released but i personally think there are better sentinels, even more so for competitive play.