Who needs this product?
Motherboards manufacturers currently put 19 NVME slots on their boards taking up space that would've formerly been used by PCI-E slots.
EDIT: Thought about it for a few minutes, the higher end boards are often times less likely to have very many slots and more NVME, and usually are the eye candy that receive reviews. Mid-end boards sometimes have more slots. But even if you have 3 16x slots and remainder 1xs it might still make more sense to buy two 1x or 3 1x NVME pci-e cards than this one 16x.
Additionally there's also the maths involved. A nice board but not top of the line plus the cost of this card and you're left with probably the same $price$ as a highest end board that has 6 NVME ports integrated onto it, so why not just buy the better board if you need that many drives. I'm still not seeing who needs this product.
The root problem is that board manufacturers often do not put enough 4x, 8x, or 16x slots on their boards. They force us to pick only boards with 2-3 at max slots, and then the remainders are all 1xers. (or absent altogether)