Oh, c’mon. More importantly, this says “Earth ponies have magic too.”
 
That, or Pinkie can change reality by booping her nose. Either of these are acceptable.

Why am I not surprised that Pinkie has magic

@infinita est lux Solis  
Well it’s possible that she may have a micro-horn in her bridge, between her eyes

Pinkie’s magic be like a old fruitloops comercial “just- follow your nose~

@sTs  
I’m sure all of them have some Pegasus/Unicorn/Earth-Pony/Bat-Pony genes in them due to the sheer amount of crossbreeding over the centuries, not just Pinkie.

So where did Earth pony magic and Pegasus magic go?

@FamusJamus  
Fluttershy likes Sailor Moon and Dragon Ball! Holy fuck! DX

@Mori  
That’s because she’s possibly part Unicorn

They have proven once again that Pinkie Pie is not normal.

@Background Pony #3D6F  
Trying to understand our beloved pony name Pinkie pie is going to be hard. She has her own logic.

@Background Pony #8A43  

If you get tired of people taking gag scenes seriously, then you’re in the wrong fandom.

@Background Pony #EE55  
There were a few confusing things around the end aside this Pinkie thing regarding the stolen Magic: Luma and Celestia as well their royal guards were going to Ponyville by walking like if they all lost their Flying powers, and only when the Magic returns they go by Flying. And what is more confusing is that in that scene only Celestia, Luna and Neighsay’s artifact get their Magic back. So by that logic the guards could fly even before the Magic returned, so why didn’t they do it? Bah, whatever, these are just details in the background, I think the storyboarders are the ones to blame Here not the Writers (for that matter even the Pinkie Magic we see Here could be storyboarders doing, after all it wouldn’t be the first time this happens. Twilight’s final Flight at the end of MMC wasn’t in the script, animators just had Fun with that, of Course creating a few continuity mistakes in the process). I loved this finale and I think it’s not worthy to overthink about these confusing details in the background, it just drags all the Fun.
 
(regarding the Flight in General thought, I think that might be Cozy Glow’s doing: She was stealing only the unicorn Magic, the magical abilities of non-pony Creatures and the powers of the magical artifacts apparently. She might have not removed Flying powers because she didn’t want to Lose her ones. That would explain why pegasi didn’t Lose their Flying power aside that dull moment with Luna and Celestia and the royal guards).

The problem with the idea that “Pinkie had magic so that she can do all those Pinkie things” is that Pinkie was also doing all those Pinkie things (e.g. getting a monkey costume / a cake out of nowhere, and transporting into Tirek’s cage) when her magic was gone.  
Heck, I think there’s a huge plot hole in this finale. In S4 finale the pegasi couldn’t fly when Tirek absorbed their magic, and in this episode all the pegasus guards and even the two royal sisters only started to fly over to Ponyville once their magic was returned. Yet RD and Flutters were able to fly inside Tartarus.

@Background Pony #494A  
so they kept their magic even though cozy glow took all the magic? it’s still magic, just different from unicorn and alicorn magic. Now I’m confused, pretty sure they made a mistake here. Just season 8 things lol

@Background Pony #4BC1  
We are not questioning her. We are understanding her.

@cursedinfernus  
They must have magic. A cutie mark is a magical symbol, not a biological or artificial one. It denotes a special ability, one that is amplified in the individual by magical means. The only difference is that we’re seeing the visible magic of unicorns and alicorns manipulated here, and that the magic of other pony races isn’t visible.

@genervt  
Well I have the answer: she’s part Unicorn.

@northern haste  

 

 
One simply does not question Pinkie Pie.

@northern haste
 
My brain when trying to find answer for this situation, weather she has magic or not.  
Before  

 
Conclusion  

Of course Pinkie Pie has magic  
>>546723t (merged)

I thought earth ponies and pegasi also had a kind of magic

People stop questioning about this weather Pinkie has magic or not, she’s Pinkie pie we don’t question about her.

Really getting tired of the fandom exaggerating Pinkie Pies abilities, taking gag scenes too serious and the writers that panders to this.

WRITERS EXPLAIN

Pinkie’s powers come from her nose, confirmed!