That's not really air cooling.
The NZXT Kraken G12 is an AIO cooler for the GPU chip; it uses air cooling for the VRM which doesn't generate as much heat. I have used the Kraken bracket with my RTX 2070 SUPER Founders Edition card.
This is similar to current hybrid cooling solutions like the ASUS ROG Strix 3080 Ti LC model:
The ASUS RTX 3080 Ti STRIX LC is THE overkill RTX 3080 Ti. It comes with a pre-filled watercooling unit, that provides cooling for the GPU and memory chips. Thanks to a factory overclock to 1830 MHz, this is the fastest RTX 3080 Ti we're testing today, but also the most expensive.
www.techpowerup.com
which again uses an AIO waterblock for the GPU chip but air cooling for the VRM and VRAM.
This is not the same as a full-length waterblock like the Alphacool Eiswolf AIO solution or a custom loop.
The NZXT Kraken works but there's nothing elegant about it. Because of the bulk of the Asetek waterblock head, it made my 2-slot 2070 SUPER FE into something more like a 3.5 slot graphics card. At best, the NZXT Kraken G12 bracket is a hack.
Today's graphics cards generate too much heat for a third-party air solution to make any difference. Air has much lower thermal capacity than water. Today's air cooling designs for graphics cards need to be customized for the particular PCB in question.
Look at the RTX 3080 Founders Edition card. With the v-shaped cutout, this is a tiny PCB relatively speaking. This card can easily be cooled with a waterblock but struggles to be cooled by air.
The main takeaway here is that you can't just clip on a 120x25mm fan onto an already thick air-cooled graphics card.