I have a collection of single hose regulators that are stil single hose regulators. When I dive the Clackamas River in high current, I sometimes dive "slick," with nothing hanging off me. I experiment in underwater swimming techniques with no SPG or inflators hose. Nothing to get tangled. I sometimes use a J-valve, and sometimes use my Scubair regulator with the positive reserve from the 1960s. It seems that all this talk of automation and wireless systems is simply getting us back to where we began. Did you know that Cousteau and Gagnan's original patent for the Aqualung talked about not needing external gauges to monitor visually? He felt that could be a hazard (external gauges) in zero visibility, I think.
SeaRat