It's a circle of tech death.... unless someone has a specific niche need to swap connections or the only available PCIE lanes are from an M2 socket i wouldn't be putting too much effort into figuring out "why" it's being sold. I've had companies procure odd things because of a "need" to make something work. For instance a cable pitch adapter for a new laptop screen I wanted to use for 4K120. They got me a couple of them to make the sale on the higher priced panel.
It's kind of like you can use about 5 different adapters for the U.x drives and convert them to/from different specs and still get the speed. Sometimes it's easier to just not ask questions.