Umm where we had no tv signal there was no phone either or at least on our o2 phones. Which makes me laugh when people say they are going hill walking with no map or compass as their phone is both.... that is when it works of course.
Done 186 Munro’s, over 200 Corbets.
I use compass and maps.
But I use my phone with or without a signal on ViewRanger never had a problem.
Even with absolutely no phone signal.
I also carry a portable recharge, just in case,
I know what it’s like to struggle in the mist.
And I have with the aid of a phone helped to get myself and others off a hill covered in mist so dense I could only see 30-40 feet ahead.
As far as I am concerned anything that helps with navigation has to be good.
But you should also know how to use a map and compass.
Use modern tech to assist, but never be totally reliant upon it.
But don‘t be a Luddite either, use modern technology wisely instead.