He's only been useless because he's been double-marked, whereas Villa has only had one player on him until he (rarely) got near the penalty area. At least by keeping Jack on, he ties down more players who can't engage in the rest of the play.
Or at least, I feel that's what Patrick was going for.
Neither. This game is insane. The previous two knock-out games played today were far more cautious affairs, I understand. Toronto and NYCFC have had a fairly bitter rivalry from the first day, and they've both simply opted to use this game to kick lumps out of each other, not to mention that Toronto were clearly absolutely desperate to take an advantage into their away leg. The play is hardly PL standard normally, but neither is it this relentless and lacking in skill.