Obviously in your case it isn't a problem, but when using multiple switch mode power supplies like that you can run into issues with inrush current. That's like the starting current on a motor. Power supplies usually limit that current to 50 amps for 1-2 cycles of the power main so wire heating isn't as much an issue as the power switch blowing up.

A place I worked at was testing lots of production units with those power supplies. They were plugging them into a 6 outlet power strip on the test bench one at a time and that always worked. For some reason a person (NOT me) turned off the switch on the power strip and then back on with all 6 devices plugged in. The power strip blew up in his hand.

Don't do that!