Because Shu Shu has done much in the manga as of late
Anyways ShuShu campaigners why dont you use super ShuShu image, it worked wonders last year
Forgot to mentioned why Apoo for me personally?
Well there are 3 main things
1. His character was presented lovely by him wanting to stay after the arrival of Kizaru and than just trying to annoy him and making a run
2. Again his character when we see all the SN watching the great war from distance, when he comments that Law is nutorious for being cruel (which makes me believe he himself is not like that)
3. Design, is unique and interesting