Yes because you gain points from it that you use to enhance your stats for standing strikes, kicks, clinches pretty much everything. The better you do and the more stamina you have going into a spar the more points you get out of it. Also as the game progresses you get tougher sparring partners who multiply the amount of points you get. For my very last spar before they forced me to retire i got 134 skill points. before that the  id average about 60-80 points a spar.