BS, it was not a bad idea until there was something better !
But we do know that the junk Mag converters were still installed in new RVs as much as 10 years after the 3 stage conv/chargers were out (as late as 2004) and proven to be fabulous.
Why,...I guess because there were boatloads left over and the RV MFGs could buy them really cheap. And even the single stage 13.8v converters were being sold by CW long after 3 stage converters were out, and advertised as the latest technology. I know a guy bought one to replace his mag in his 2002 MH, only to find out a few months later that the 3 stage had been out for years already, and that he had actually bought a very slow charging converter.