The brake limited differential (BFD) is a virtual LSD, the brakes keep wheels at nearly the same speed just like the clutch packs in a LSD does, and it only does it when needed.IMO it's not worth it, as the current open diff system, directing power by using brakes, works well.
There's a half dozen reason why a true LSD or Locker would provide better performance, but like you said, it works well.
And I have to agree, trying to engineer your own retrofit of the ELSD would take a lot of time, expense and frustration. Meanwhile you've got a virtual LSD, perhaps not as good but still good.
Noise and roughness during normal driving, more maintenance, wheels breaking traction in lower traction condition, which an inexperienced driver could lose control. Serviced improperly those characteristic could be worse.What was wrong with the mechanical limited slip differentials that made them want to replace them with this complicated mess?
They perform better, but they do have drawbacks, so they come up with different answers that have their own sets of drawbacks....