For one, it's still uncertain if and when you'll get banned after playing online using the Mig Switch--the team claims so long as you have a valid certificate, card ID set, and card UID, and a fully complete game dump, you'll be able to play online just fine. Whether or not Nintendo can notice and take action is something that will take time to see. In order to obtain updates and DLCs for games, you'll need to be online to download them, as the Mig Switch can't load those files itself.
This leads into another quandary. The three aforementioned aspects--the certificates and IDs--come from a backed up copy of a Nintendo Switch game. If someone were to illicitly share their certificate online, there could be dozens or hundreds of users using the same cert for multiple games, across multiple systems, at the same time. Since you can obtain a certificate from a physical game, there's growing concern as to how it could affect pre-owned backed up copies of games that might have had their certificates used and banned. We know for a fact that Nintendo has banned gamecart certificates in the past, as found by scene memeber SciresM back in 2018.
If you're interested in seeing the Mig Switch in action, there are a handful of reviews from notable emulation-focused YouTubers.
So far, what are your thoughts on the Mig Switch? There's plenty of interesting quirks to the device, from its usage, to its mysterious development team. Have you ordered one, either to test out, or for use on trickier to softmod Switch revisions? Or are you staying away from anything to do with this flashcart?