Thread: Smartphones for GPS navigation.

Ok so sorry if this has been covered before in other threads but I searched and the only one I found was from 2013 which is a long long time in smartphone years!
What I would like to know is whether it is practical and safe to use a smartphone app as a navigation tool in the New Zealand backcountry and, if so, what apps do people have to recommend? The old thread cited battery life and waterproofing problems as arguments for a dedicated GPS, both of which id have thought have been largely voided since then, by advances in technology, solar chargers and power banks etc.
The reason I ask is I am trying to decide between an Inreach Mini and a 66i, obviously, if I can use my phone as a map tool, the 66i is an unnecessary (and large) expense.
Looking forward to hearing everyone's thoughts and experiences.
Thanks.