瑜伽師地論略纂 15.57

15.57

「受用業果增上，立五受根」者，其憂非果，然得果已，亦於果位中起受用，故言受用果也。

Regarding 'predominant in experiencing the fruits of karma, five feeling faculties are established': grief is not a fruit; however, having attained the fruit, one also gives rise to experiential enjoyment during the state of the fruit, and therefore it is said to 'experience the fruit.'