It was obvious to her! Every Inkling and Octoling knows the value of having a good ink tank. Just because you don't live in an ink-based society, Edge...

But she can understand the confusion. After all, her physiology was pretty much the only one on the train that was made this way. "Because all my weapons need ink to be used. I've been relying on my own ability to make ink to throw it with the bucket. It takes me about 5 minutes to get enough ink for another shot. But with an ink tank I can charge up to 14 shots an use them immediately! And I can dive into my ink and recharge the tank any time I want!!"

"And..." Oh... oh this next thought gets her starry eyed. "I can clean myself."