It's because he has to exert energy because someone is being physical with him. He has had cakewalk as far as the pgs he had faced. They have either been terrible or severely injured.
i understand that, but curry always has that sick 3-5 min run against anybody. you can't hold him down for 48 min because he shoots off dribble. and even if you hold curry down warriors are deep enough to beat anybody. they would still be the favorite against any team