I think the point is, and everyone can agree with, is the giant caves (24 hr.) makes you lose and waste diamonds (weather the sum of the outcome may be disputed). The free caves (10 hr. or less) are free (0 diamonds) and you gain diamonds (because they are free) and the giant caves cost diamond (50 diamonds each cave) and you don't get more than 50 diamonds back (or rarely) in a 24 hr. period, so therefore you lose diamonds. I guess the only thing going for it is convenience, which people already pointed out is it only takes 5 mins. (with the game loading) to open and clear the mines. I too only do the mines twice a day, once in the morning before I go to work and once at night before I go to bed (usually about 6 am then at 7-8 pm). I do the other dailies through out the day, but that's for another thread.