I guess that’s because hearing aids is a restricting term and these are more versatile. Furthermore, probably calling them “hearing aid” would lead to costly clinical regulation that they cannot afford as an open-source research device.
Cool to see them pop up here, as my colleague Tobi built them here at our lab and is now pushing a spin off.
Actually to get an impression what is possible with ear sensing I am still fascinated by this application Tobi did before building openearable, which uses in ear muscle contraction for doing interaction (next song, etc):