Travel (providers like Saily allow you to take a temporary sim for a country you’re visiting, basically what used to be the people selling sims at the airport. eSIM makes it less shady and basically one-click) [maybe multiple of these if they travel often because different providers are better in certain regions]
What are your use cases for all those SIMs?
Three uses I could see:
Extrajudicially unlicensed medication dispenser.
Rug Realer