I just bought an 08 prius.
I read the manual section on driving and I don't fully understand
what the purpose of the "B" mode is.

if I am decelerating, what is the difference between D and B modes?
when is the B mode beneficial and why?
In both cases, the battery is being recharged.
The manual has a warning about not driving in B mode for a long time.
what are the drawbacks of the B mode?

I appreciate any clues

thanks