There’s some exciting improvements to bendy bones in the talks, thanks to the work of Sam200.
The code submission is under review right now (2019-04-04):
https://developer.blender.org/D4635
With this proposed change, mesh vertices are deformed by the mix of the influence of the two closest b-bone segments, giving a much smoother deformation.
I was pretty happy with it before. and its not that you get a massive slow down by just increasing the segments. I dont think its neccesary.
I was pretty happy with it before, too. But now I will be even happier, as this will help in certain use cases. In the past I’ve had problems with the lack of smooth deformation, and this will fix that. Makes the bendy bones much more flexible (pun intended). 
Thanks to Sam200!
The smooth interpolation is a great side effect, but the main goal behind that improvement was fixing how shapekeys interacted with bendy-bones.
Before this change there was an artifact where the shapekeyed vertices would “snap” between segments, like this:
This change fixes that.
PS: just to keep up with the history, Blender dev. Alexander Gavrilov refactored Sam200’s initial submission, so what was merged is that revision.
