Mine came with an adapter. I assume Galaxus adds these adapters and it was simply forgotten. At such a price, I would also have expected a Swiss plug, but they are probably procured through a parallel import. That's why it's cheaper.
But I had one with the Kärcher that wasn't needed....

Sometimes the plug is forgotten. But as soon as you call, a new one is delivered free of charge. This is independent of the device.