I don't know why anyone uses a switching power supply in the first place
For DXpeditioning? Weight. If you take a station, any station, overseas, you rapidly learn to obsess about weight.
There are surcharges in some cases. In others, especially the "American Eagle" style puddle jumpers that are often the last leg of these things, there can be
absolute weight limits as well.
It isn't always a question of surcharges (which can be hefty enough). Sometimes, if you are overlimit, you just don't fly. Those smaller planes need to have the weight in the belly balanced out.
When I traveled to Placentia, Belize, I literally flew on a Cessna. Commercial grade, all weather instrumented, larger than a pleasure craft version, but it was actually a Cessna.
I also helped a friend take his immensely clever 2m EME station overseas a couple of times. The antenna system, rig, and amp was
very carefully divided into three major duffel bags (which also had to meet various limits about
dimensions also). A lot of stuff was done for the sake of weight -- and everything had to break down to a maximum length as well.
The three bags clocked in at 49.5 pounds or so each. By very careful design. You also had to make the kilo limit (I think it was 22 or 23) in this otherwise metric world. In any case, we flew in just under the limit (weight, height) in all three bags and had to put an exact inventory of parts in each one.
BTW, commercial antennas for 2m EME just don't fit these dimensions. He had a
lot of custom aluminum in that antenna.