I am. It is a semantic difference. Single entities get referred to by a single word. If you use a word group to describe it, it means you don't consider it a single "thing", but a "system" described by the relations of single "things".

The composed word also has a specific meaning that the same words with space between doesn't. For example "das rote Kraut" – "red herb" and "das Rotkraut" – "red cabbage". Also suppose "red cabbage" was grown in abnormal conditions, so it doesn't have the color pigments, it is still "red cabbage", but not "red" "cabbage". This is awkward to state in English, but no problem in German.