Can You Help me Understand This SATA NVMe PCIe SSD Gen

How are PCIe Expansion cards not way more popular pcie m2 slot is a slot that can interface with SATA , PCI Express pcie slot pinout 2 adapters provide one slot for PCIe, and one for SATA True dual PCIe cards have x8 connector, for example AOC-SLG3-2M2 To fully

pcie 30 in 40 slot AS2280Q4U's blazing-fast PCIe Gen4 x4 interface is fully compliant with the NVMe standard With sequential readwrite performance of up to 7,4007,000 MBs,