I was tempted to buy one, but the only ones available currently for an OK price are 256GB and I don't think I'll need the extra install space at launch. I'll be playing Mario Kart (download), and Zelda (card + download, not sure it'll be the entire game). Getting Donkey Kong in July, maybe Kirby when I'm done. I don't see myself needing one in the near future, by the time I might need one the Switch 2 will probably have made them mainstream and prices will go even further down so might go for a 512 or a 1TB.
Apple to oranges lol
You can't swap out an SDD and add in a new one in a few seconds. Massive size difference.