JumpEF is better than grounded EF

[Noge]

If you haven't noticed this, just try to press jump and SideB at the same time, or jump then SideB almost same time, palutena throws Explosive Flame a little bit higher while cancelling the jump with a wavedash-like motion. It's easy to perform.
This makes it harder to jump over it while covering the ground as well, making EF quite a lot safer; also makes a difference throwing EF vs opponents in platforms.

I'm seeing palutenas not using this / not knowing about this in tournament finals and such.

 

[FishkeeperTimmay!]

I think that is the "Attack Cancelling" mechanic being applied to a Side B option. I'm sure that as more players become comfortable with the mechanic, we will be seeing it applied to almost everything. It has a lot of utility.