> "[compounds] tend to be written in separate parts. This would be an error in other Germanic languages such as [...] German, and Dutch. However, this is merely an orthographic convention."
I'm not sure Wikipedia is right here. It's not necessarily an error to write a space in between two words: it just changes the meaning, and it's an error if the meaning doesn't exist (just like in English: "ahorse" doesn't form a meaning like "alike" does, and so is likely a typo for "a horse"). It's also not "merely an orthographic convention" the way that, e.g., starting sentences with uppercase is a convention that could easily be changed because the sentence separator "." is already there.
The space separates two words. Having no space means it's one word. Adding the space means that what came before must be a different word, like an adjective or a preposition.
Take something like "patient data": is this data patiently waiting, or is it about data belonging to patients? In Dutch/German, "patientdaten" is unambiguously one thing and "patient daten" is unambiguously another (when pretending that "patient" exists as an adjective in Dutch/German, which it actually does not; but examples where it also exists as adjective are plentiful, see <https://news.ycombinator.com/item?id=40399141>).
