I think I started during the summer event, so I wasn't strong enough to get to the end battles, and I haven't yet seen a need to buy rations or FB tickets, but I can see how it would be useful. I guess the plan for now is to keep hoarding, and if I end up with more stashed than I think I need, I can drop the 1500 on summons.

I like the constant free exp from the dojo, but it's such a drop in the bucket compared to exp cards from events. I'm certainly not feeling tempted to drop 1000 koban on another slot.