Good to know about SD cards.
The problem of audits is knowing who to trust with the audits. And trusting anyone at all runs contrary to the don't trust, verify ethos.
If we trust the cable, what else gets trusted? Should we dispense with a screen, like Bitkey did?
I do want my airgapped system audited, to have the second set of eyes on it. But there's always the question of: who audits the auditor?
The matter of checking QR codes, and the difficulty of doing it manually, does make me wonder if there's room for a device that, also offline, can be used to take translate the QR to de-serialized format to make checking the full psbt an easier process. Probably a niche use case, especially given laziness and quickness to trust, but it could be useful for the truly paranoid.
As for the assumption that 'they can, but they won't' -- this is precisely the sort of presumption I see as common and take issue with. Some people will cut corners either way, but we should be letting them know explicitly they are doing so, rather than operating with rhetoric suggesting that they are using best practices when in actuality there is trust they are extending unwittingly. IF you are not going to verify everything, AND are willing to trust an auditor, it sounds like you're suggesting that you can achieve a better security model without an airgap than if you aren't going to verify everything and use an airgap. No complaint from me there, but those conditions should always be explicit. Users can choose to consent to risk taking, but when suggested to take risks they're not aware of, well, I have a hard time distinguishing that from being intentionally misled. I don't want to quite call it scamming, but it's adjacent especially when there is financial gain from selling these products that require the trust model.