Why? The only change is that the output stage is inside-out compared to a "normal" amp, and noise is usually generated by the front-end anyway.Noise is another issue
That.it requires 2 rail windings in the transformer, 2 $2 bridge rectifiers and 4 rail filter caps. As 2 x 10000 uf filter caps are cheaper than one 22000 one, probably saved money right there.
QSC or Shure have used this system for many years, it helps when bridging power stages together.
This particular example also shows the output devices can probably be bolted onto the heat sink without insulating thermal pads.