There is no system in the world which is 100% safe and secure and completely impervious to all attacks. However, this article makes it sound like stealing data from an air gapped machine is almost trivial, which it obviously is not. For any of these attacks to work, someone must first gain access to your airgapped computer, install malware on it, place some kind of microphone, radio receiver, or similar in the same room you would be using it, and do all this without it being noticeable. For most people who keep their airgapped device inside their locked house (as long as you are not silly enough to plug in a random USB drive someone gave you to your airgapped device), then that is next to impossible. Airgapped wallets set up properly remain very secure.