Probably because it's way easier to pull a SIM out of the package and stuff it into the reader than it is to go through the QR code/web site/phone app you need to get the eSIM up and running for your provider.
What I'm really curious about is the money trail. These cards weren't bought in one off cash purchases or via some penny ante crypto reseller. Someone bought in bulk using real money. They probably had to talk with the salesguy at the MVNO to make an order that large. This kind of thing must leave a footprint.
The bar to getting access to MVNO sales is actually extremely, extremely low.
They're ordering and activating maybe 20-50 at a time, and ordering that number of SIM activation kits from dealer supply houses is extremely normal. Activation typically also is at little to no cost as well to dealers in this market.
FWIW: at sixteen, I somehow managed to get dealer access to a CDMA MVNO. I was able to activate accounts on the fly with $2 of "free" credit to start the user off, with zero cost to me. I still get emails to this day over a decade and a half later from various cellular resellers offering me bulk cellphones...
What I'm really curious about is the money trail. These cards weren't bought in one off cash purchases or via some penny ante crypto reseller. Someone bought in bulk using real money. They probably had to talk with the salesguy at the MVNO to make an order that large. This kind of thing must leave a footprint.