It looked like the spl levels at low frequencies were comparable to other IEMs, with a peak in the high frequencies surpassing the other IEMs, and at a lower THD. The peaks could easily be equalized within an active system. These seem ideal for optimizing small Bluetooth audio devices like the AirPod or hearing aids, so I don’t think any of your cons apply for this use case. I agree with the final statement, but it’s not clear that the first 3 are actually non issues in an AirPod scenario.