I don't have any details, but on their public website, they highlight LLNL (ELI5: US nuclear weapons research lab founded by Edward Teller) as a customer. I am not 100% certain they require airgapping, but it is totally conceivable that them or similar customers in that vein do. Oxide business probably selects for a biased sample of such customers (the customers that don't have esoteric requirements also have public cloud options AWS/GCP/Azure to choose from).