Action sports cams, dashcams, handheld gaming device such as the switch and steamdeck, I'm sure there's plenty more application. All fairly niche but it's a market
The Nintendo Switch has sold 132 million units, so I'm not sure how niche that is. Presumably the successor is going to keep using microSD cards, and filesizes will increase in line with graphical capabilities.
I feel gaming devices are the primary target...as someone who used to shoot wedding videography a few years ago, there is a limit of how much footage you want to store on one card - if only because you can easily lose them. The smaller storage limit is a feature, not a bug :) It forces "normal" users to actually figure out a backup solution. Most action cams are going to take a long while to fill up 2TB.
I have a steam deck and have no interest in a 2tb sd card, i am subscribed to some steam deck communities and the preference, given the reliability of sd cards, is to have multiple smaller rather than risk a single big sd card to fail and having to reinstall them all
I have a steam deck and my primary interest would be to use it on mine. I'd apply the WORM method with it. Load it up with ROMs and only ROMs. I have a back up of all that data so suffering a failure would be a minor inconvenience.