You should all definitely go for it. It's likely the staff aren't saying how many will be featured, because they plan to decide based on how many of the works they want to feature.
But even if you don't get in the collection, you might still catch somebody's eye and end up getting featured at another point. If there's an opportunity to get the staff's eyes on your work and to let them know it exists, you should always take it.
Good luck, everyone! I hope to see some familiar faces in the collection!