Air gapped?

I am slightly confused by the whole concept of this product. In the introduction video the founder claims it’s an air gapped system, and “your keys your crypto”. However, if youscroll down it tells you to download an application from your respective app store. It then states after install the application will generate a 12 word passphrase, the you use NFC to write the details to your phone. I mean, I am no crypto expert in the slightest, but wouldn’t that mean the application has your private keys? How are you supposed to write them to the card if the application doesn’t. And unless you were able to sideload the application, your phone most likely isn’t air-gapped. I suppose one could argue they are just spewing the words out, but that’s how you would generate the keys. The application would still have to convert the passphrase into a secret key when interacting. So even if they only had the words your secret key is still compromised if they were to save that data.

I mean unless their code is open sourced, and I don’t have to pay $99.99 for a chunk of metal with a NFC element it’s going to be a hard no from me. Seems like you get get the same effect with an NFC sticker. Just create your own crypto app with NFC support, create a truly air gapped method to write the private keys, and presto, I just saved you $99.99. Sounds easy enough. 😂

A screenshot of www.getarculus.com/getting-started/ as shown on January 10th,2021 describing a setup process involving the creation of a 12 word phrase for secret key retrieval
Could someone comment if they know of a way to get a passphrase without knowing the secret key?