The Switch doesn't need these cards, it's more of a nice bonus.
The internal storage for a Switch 2 will likely either be UFS 3.1 or better or NVMe itself which is what Apple has used for ages on the iPhone. That's already blazing fast anyway.
So that was never really a big deal.
Maybe though Nintendo may use PCIe 4.0 style lanes for their next-gen cartridge format and they could indeed then have 4GB/sec bandwidth, which would be cool as well if the SD card commission doesn't want to play ball and just sit on these cards.