No doubt someone will come up with a much more comprehensive answer, but just to get a head start…

It's not a shuffle.
I've never really thought about it before, but the piano is clearly in triplets not a shuffle. It establishes that by the end of the second 'real' bar, with the descending bass line. I'd have probably written it in 4/4 triplets, which is what it feels like in my head, but I guess 12/8 might be easier to read.
You couldn't just write it in straight 8s & write "swing" at the top, like you could with a shuffle.

No doubt someone will come up with a much more comprehensive answer, but just to get a head start…

It's not a shuffle.*
I've never really thought about it before, but the piano is clearly in triplets not a shuffle. It establishes that by the end of the second 'real' bar, with the descending bass line. I'd have probably written it in 4/4 triplets, which is what it feels like in my head, but I guess 12/8 might be easier to read.
You couldn't just write it in straight 8s & write "swing" at the top, like you could with a shuffle.

*It's not a shuffle because it really knows where its triplets are, right the way through. If it was written as dotted or notated as 'shuffle' or 'swing' someone unfamiliar with the piece would probably swing it just precisely the wrong way. It would be like writing Everybody Wants to Rule the World as a shuffle.
12/8 or 4/4 triplets takes away that temptation.