The student is forced to learn new grips since the collar, sleeves and pant legs are no longer available. That awesome spider guard is not so awesome without the sleeves to control! You can adapt your bjj to use non-kimono grips like under and over hooks, collar ties and wrist controls. You will gain an new understanding of the “handles” on the human body and how to control an opponent. The no-gi style of jiu-jitsu tends to be a faster, more scrambling based game and those more athletic and younger practitioners tend to find advantage in that. Without the kimono, collar chokes are eliminated and a considerable part of the arsenal of a bjj fighter disappears. The student now must concentrate on guillotines, Darce, head and arm chokes. All of which provide variety in your learning and can also be used when you put the kimono on. In my academy, when the hotter weather comes, it can be a great relief to take off the kimono and train in the cooler rash guards and board shorts.