I find Apple extremely annoying when you disable iCloud: they keep reminding you to enable it on every occasion (updates, freeing up space, going through photos, etc).
Looking harder, I think what's happening is I do have iCloud, I just don't use it. I don't have automatic backups of photos, I don't have iCloud Drive (what it prompts me for on software updates), etc. Everything is unchecked except Find My iPhone. I haven't had any downside from having iCloud in this active-but-unused state.