Competitive coding, despite superficially involving typing code into an editor, has almost nothing to do with working on large pieces of software. It's a lot of rote memorisation, learning algorithms, matching them onto very particular problems, and so on, it's more of a sport. Just like playing too much bullet chess can be bad for your classical chess I can honestly see how it gets into the way of collaborative work.
At lower levels like where I'm at, players are prone to mistakes and blunders, so having a good eye for tactics allows you to take advantage of those moments in the game as well as prevent yourself from getting into a bad situation.
But at elite levels, tactics have less importance (as he says in the video he estimates it drops to 50%) as every player at that level is extremely solid.