In this case it is. Privacy is about control and unless you have absolute control you cannot guarantee any privacy at all. And you don't control your phone's operating system, the GSM module OS/firmware, the carrier, the client applications and even the radio signals.
What you want is an illusion of privacy. The two are vastly different.
This is like saying there is no privacy for email so here I post my password on pastebin.
I control the software I run on my phone, so I have a better privacy. It's not perfect I know. But doing nothing because it's not perfect is the biggest illusion of all.
1) You do not control the software you run on your phone. You control almost none of the firmware, which if malicious could easily steal all of your data with impunity.
2) Simply controlling the software is not enough. Cell towers are programmed to track your every move and accessing this information is easy for the government.
3) Even if you did control the software you run on your phone, it implies nothing. The trivial example would be that clearly even when you bought the phone you controlled the software you ran on your phone.
3) Detecting usage of tethering is trivial. The stopping the reporting of the use of tethering just makes it easier for them.
4) DNS settings do not matter. Google's DNS logging policy is fine - and in any case they get no information since your phone provider will be using NAT so they'll have no way of differentiating between your phone and any other. There's no large benefit to privacy by not using Google DNS, but there is a performance cost.
5) You say that you feel safer - this is exactly the problem. All of these apps you've specified could easily have security problems in. They're not widely used, and likely are not widely reviewed. Following this guide gives a brilliant false sense of privacy, but likely little real additional privacy.
