Like Clarice, I can hear someone whisper on my deaf side. And, as she mentioned, it's really just an "illusion"; I'm not really hearing through my deaf ear - just feeling like I am.
BAHAs, like most hearing devices, aren't perfect. They tend to pick up all sounds; not just give you the ones you want to hear. Filtering out unwanted noise/sound is difficult for them. So there are limitations in noisy and/or crowded environments. But improvements are being made all the time. When I got my first BAHA device (a Cochlear Divino) in 2008 it had what is referred to as two "channels". A few years later when I upgraded to the Cochlear BP100 it had 12 channels (the Oticon Ponto Pro had 10). The more channels a BAHA device has, the better is it at filtering out unwanted sound because there are more "places" for it to "go". There is a huge difference between my one channel and my twelve channels. My Divino also only had 1 setting; my BP100 has 3 settings. That helps too.
And new devices - by both Cochlear and Oticon - are being introduced all the time. The technology just keeps getting better and better.
Jan