Smartwatches could potentially be used to steal data from or launch attacks on air-gapped systems - I wonder how far-fetched that really is

SmartAttack relies on exploiting the microphone of a compromised smartwatch to receive ultrasonic signals from an infected air-gapped computer. Ultrasonic transmissions operate between 18 and 22 kHz, just above the range of human hearing, and can carry data such as keystrokes.