I don't find this article very helpful. As others say privacy isn't a boolean. It is a spectrum. Glad they mentioned faraday bags. The location off switch isn't a lie. It however is misleading. With your phone radios on your location is known by the phone company. The only way to avoid this is to disable the radio. If you don't trust the OS, IE you aren't running Graphene or CalyxOS or even if you are and your life depends on secrecy then don't have a phone or use a faraday bag. Depends on your threat model for sure.