I don't presume to speak for Masaki and Amanda of course, but until one of them can speak to the reason for Marika's cup feeding, I can say that it can be helpful in the short term to help a baby who is intent on taking her own sweet time to figure out the whole breastfeeding thing.

The technique of taking formula from a bottle is completely different than that of breastfeeding, so if a mother wants to breastfeed it's generally best not to use a bottle, especially in the early weeks. If a baby is having trouble figuring out how to nurse (Amanda mentioned that latching on has been a challenge), cup feeding can keep the baby sufficiently nourished until she figures out what she needs to do without confusing her with an artificial nipple.