Smash 3DS Does the game have an "angle/directional assumption" system?

[Kyasma]

I am not sure where to ask this, and I'm not sure if this has been addressed or not, but I was toying around with Sheik and noticed something (doesn't look Sheik specific, but it does not happen with all characters).

If you angle your analog to around 45 degrees (up and side, have not tried down and side), depending on your location a different special will activate.

For example:
Sheik - On ground: Nade/ In the air:Vanish
Toon Link- On ground: Boomerang/ In the air:Twister
Greninja: Always Shadow sneak.
Zero Suit Sammus: On ground: whatever her side B is called/ In the air: whatever her up B is called.
Ike: Different specials


I am not sure if this is intended, but I find it very odd because of Greninja's exclusion, and maybe a few others I have yet to test. One idea I considered was that when you're on the ground, since you are moving sideways, the direction is side, so it would use side b, and while jumping, it is up, so it would use up b.

The only problem I came across with that idea is that when jumping I'm still moving sideways, and I could use any side b I wanted in the air too.

Does anyone have any ideas?