Right, I get the idea that by the end, Reimu's overdrawn her balance, so no more coins for her... but if she's a bank, it still begs the question of who put the coins in the bank to begin with?
This one was a follow up from a previous comic on which this Reimu was genetically modified to be a purse, but for some reason she ran away, so all those coins she was "giving birth to" ? they were the money miss put in there.
It's from the previous strips. Reimu is yukkuri bank number 2. She escaped home when seeing their owner draw the saving from number 1 (with QN QN hammertime).