Since it’s modular (removable), as far as is reasonable, Purism shouldn’t restrict what M.2 card the customer can put in (although I would suppose that anything that uses PCIe / SATA via M.2 may never work e.g. even if you could find an M.2 storage device that physically fitted, it wouldn’t work).
Some customers may want a WiFi card that does not do Bluetooth. Some customers may have no need for either.
With the speeds I am seeing at the moment, I would be happy to see anything like realistically achievable USB 2.0 speeds, never mind about USB 3.0.