Unsure but as nvme doesn't require any brackets etc. they might have kept into consideration while designing the most common area (between pci-ex slot) etc. across major mobo. mfg brands and came up with this.
Also, only a serious gamer or someone who like some luxury aka fancy stuff or the actually needy one who might need it will go for it.
Expecting it not to be on par with cpu cooler pricing else it might cost more or less with AIOs which imo wont be a great purchase!