Huh I didn’t know that! So does it mean that websites internationalize even the salutations? Do they replace “Hi Joe” with “Good day Mr. Brown” in Germany?
It depends. If it started in an english speaking country, then more than likely not for a long time. If it started in a germanic one, it'd almost 100% be the last name.
It has less to do with where it started and more with the language and what field the business is operating in.
I was working for a UK steel supplier and they would address all their email recipients with their first name. We had to change this when internationalizing into German. If you want to sell to Germans you are much safer to use a more formal tone.
Slightly related to that is the formal and informal you that exists in a lot of languages.
I was also working for a German fashion startup mostly targeted at young women. In German it was fine to address everyone by first name and the informal you, but when translated the page to French, we could keep the first name but had to change the informal you to the formal one.