Honestly, I didn't pay much attention to the Bone Conduction Driver and nor was I looking for it.
I tend to first focus on what the IEM/headphone gives me in terms of enjoyment and satisfaction. If I find that to my expectations, I then delve into the technicalities. Earlier, I used to fall for the fancy terms, marketing, and advertisements various companies use, or the technical capabilities advertised but after a few years in this hobby, I prefer to keep things simple. I know I like the hybrid sound more than an all-BA setup. Thus, from a purchase perspective, I test hybrids. Only if I like them, then I get into the details of drivers, technologies, etc. I have seen that less is more many times, e.g., like in the case of the 64 Audio Trio or the Final E3000 which I purchased and thoroughly enjoy!