That’s exactly what I’m thinking as well. When and if it gets confirmed that the cartridge slot is exactly the same (don’t see why it wouldn’t be) and can read Switch carts, that will probably be it.
More than likely though, Switch 2 carts will have a different type of encryption that things like the Mig switch probably won’t be able to read without an update
Outside of the few flashcarts I have, don’t really know the history behind the creation of them. Probably worth looking into the everdrive made by Krikzz as a starting point.
My Life in Gaming also did a few videos on the subject a while back. Here’s one of them: https://www.youtube.com/watch?v=fuHA3k-y6PE
For me personally, I think it’s a good way to play rom hacks on original hardware. Definitely a good way to also not put as much wear and tear on the cartridge slot either