That gentlemen makes some good points because he uses a holistic approach to packing. He has reduced his dive gear to a minimum in amount and weight and uses his cloths for padding. You are not going to carry a stainless steel backplate, 30+ pounds lift wings and multiple regulator sets and carrry a well equipped camera rig or pay for it $. Something has to give somewhere. For example, it is often said that braided hoses do not save any weight and I would tend to agree except that they do. If I bring two regulator sets, idenntal hoses, 40 inches primary, 22 inches secondary, 30 inches spg and 20 inches wing the difference is about 8 ounces and two reg sets that is a pound. Even half a pound is a savings. The fins, I find the Go-Sport or Eddy with booties to be every bit as light and travel friendly as full foot fins and open heel fins. And the Go-Sport and similar are usually a little shorter than full foot fins because the pocket is shorter. And you can stuff your masks inside open heel fins leaving plastic mask cases behind. You can further reduce bulk and weight by going BCI integrated inflator with a single long hose (40 inches) primary., larger arms, more powerful strobes (maybe), a mirrorless and a full framer are just going to travel larger and heavier than a compact like a S90 or the current equivilent, the Canon GX7 or Sonly RX100 series.
Not sure about compacts being as heavy as a full frame. My compact Canon S90/FIX is able to travel much smaller, one wide angle wet lens, one macro wet lens. That vs multiple ports, WWL-1, CMC macro, multiple camera lenses and a macro lens and port.