I'm mostly serious, though I really don't know why 1×2 exists and why you'd build a part that supports it but not 2×2 (or, alternatively, that supports it instead of 2×1, which is, but for a name change, an older standard with the same nominal bandwidth), and the 2×2 will also support 2×1.
But maybe there is an electrical engineering reason why it might be practical to do 1×2 but not 2×1 in some device.
But maybe there is an electrical engineering reason why it might be practical to do 1×2 but not 2×1 in some device.