This almost sounds like BS to me because in Europe all home dryers and washing machines come with a normal Schuko plug. But perhaps there could really be an issue with contact resistance since US homes are wired for 120V AC instead of 230V AC, so the amperage would be higher at the same power as an EU device? Still, while I don't know about US plugs, Schuko ones are rated for 16A. This means almost ~3.5KW. At 120V that would only be 1.75KW, but surely that's enough?
Ok, I wrote all that but now I looked up actual power consumptions, here we mostly use heat pump dryers which run at about 1KWh max. However, vented/condenser units seem to use 3-5KWh. So that would be very bad if you are using a standard 16A plug that wouldn't even handle half the required power. So replacing the junction box with a plug would be a VERY BAD IDEA on a vented/condenser dryer!
Thread tax: idk man, good in some ways bad in others, winter time and loneliness are always a bad mix, but such is life and I have plenty of things to keep me busy. I'll just keep on keeping on.