Ah, yes it’s for personal use, true. But the meaning of personal item as it relates to customs means an item that you take with you on the travels for your own use, so the assumption is that it leaves and re-enters your country with you. So that there is no net export or import involved.

My claim, if asked, would have been, that I always use two phones and I just took both with me when I went to Germany and took both back to Switzerland.