Greninja uair after footstool

[Physical_Chess]

I've been thinking about picking up greninja and have been watching a number of videos with his footstool combos. I understand why you use the special moves after a footstool to kill momentum, however I have seen two videos where the Greninja uses up air after a footstool instead of throwing out a water shuriken. What purpose does this serve? I have included a link to one of the videos I witnessed this in where the Greninja does this in the clip beginning at 1 minute 50 seconds.

https://youtu.be/AnmFjt8-FN4?t=1m50s

 

[free33]

I've been thinking about picking up greninja and have been watching a number of videos with his footstool combos. I understand why you use the special moves after a footstool to kill momentum, however I have seen two videos where the Greninja uses up air after a footstool instead of throwing out a water shuriken. What purpose does this serve? I have included a link to one of the videos I witnessed this in where the Greninja does this in the clip beginning at 1 minute 50 seconds.

https://youtu.be/AnmFjt8-FN4?t=1m50s

it's probably a timing thing, since it can be difficult to judge exactly when a character is vulnerable during a getup. It keeps a rythym going that makes your timing correct i guess.