skay53464 I have thought of that too, but "operating system" isn't totally precise as well. The "iOS" Pro version does also work for what Apple calls "iPadOS" - given the different name they could be considered different "operating systems". That's why I added the example in the FAQ text with the iPhones, iPads, Macbook.
Also, people may wonder if "Windows 10" and "Windows 11" are the same operating system or not. Not sure if there is the perfect terminology to explain it in one sentence.