Breastfeeding 2 yr. olds +

I have a serious question. I think it's great that moms breastfeed past the "traditional" ages of let's say 2 yrs. old so that their children can still get the benefits of breast milk, but why do you still allow them to latch instead of pumping and pouring it in a cup? Seems like most kids drink out of a sippy cup by that age so why latch? Again, this is a serious question. I'm seeking understanding, not rude comments.