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.