So, thanks to Niero, we know that Chieri's condition is not an isolated incident - there are at least two giants, and possibly more that we don't know about. In addition, since Niero was a giant long before Chieri was in the backstory, we know that whatever made these girls giants was not a single event - it happened multiple times at different times, and therefore could happen again in the future.
Here we have a brand new character who has little to no connection to any of the existing characters, and her presence doesn't inherently mix up the status quo of any existing relationships in a notable way. Despite this, she gets introduced with an entire chapter focused on her and establishing her backstory, suggesting that she's going to be a major character in the future. In this establishing chapter, a key plot point is how Ryou laments her inability to keep up with Chieri, largely due to the difference in scale between them.
How much do you want to bet that there's a growth spurt in Ryou's near future?