What is this game's monetization model, by any chance?

Is it a format where songs are released for free like in Project Sekai, and character illustrations are obtained with paid currency? If so, it seems like a game to be slightly concerned about. Games that adopted the same monetization model included "Touhou Danmaku Kagura" and "BanG Dream! Girls Band Party!"... Both failed. (The Korean version of Bang Dream! Girls Band Party! failed) I wonder if this BanG Dream! can survive...