I now have the cheaper scanner
www.digitec.ch/de/s1/product/hp-scanjet-pro-4500-fn1-scanner-11819418
(a few months ago I had already bought the more expensive model).
It is exactly the same product! (CH power cable is missing in the scope of delivery).

so I would say the same product was registered 2 times... what amazes me is the big price difference!!! The question should actually be answered by Digitec Product Management.