In retrospect, it's appears to be still open for debate as a universal improvement. I do think it can be an improvement sonically on a bass, but I would listen to a serious sound engineer doing an A/B test to inform me of an objective difference. Same with nut material - there's plastic, bone, brass, graphite and various hardwoods. I've used all of the above on my basses. One basses sound improves using say, brass, while using brass on another throws off that basses sound.
Also, I'm not enamored by they way they look on vintage 60's/70's Fender basses, but hey.., if that player feels it's an improvement then who am I to say it isn't. Marketing-wise, Getty Lee putting one on his 70's J gave everyone permission to mount one w/o needing to hear a difference - looking like Getty's J is good enough for some players. I have used the Hipshot KA bridge which I think is a better design based on that platform and looks a bit better. At the end of the day, the Schaller 3D is a much better HM bridge design and not as hulking as the BA. It has fully adjustable saddle height/width, has brass riser-plates for body/neck height discrepincies and is just slightly larger than a standard bent-plate bridge. It has stood the test of time (born in the 80's) still being used on many basses today.