If you want to compete in Judo (or any sport for that matter), you need to be able to go the distance. Not just the full 3,4, or 5 minutes as it is, but also be prepared for another 3,4,5 or even 20 minutes of Golden Score. You need to be as fresh after 10 minutes as you are after 2!
Don't believe me? Read a Judo biography or two - In his 'Game of Throws' - Neil Adams talks about how he'd beat the students in his dojo at footraces - even though they'd cheated - AFTER he retired. Ronda Rousey talks about training to win a gold medal, ON YOUR WORST DAY.
Years ago, I went to San Jose on business and decided to try out a class with the vaunted SJSU Judo team. I found out from talking to the students that they were doing Judo, Cardio and/or Weights 6 days a week.
The bottom line - if you want to succeed, you need to be conditioned. And if I want to compete again, so do I.