GPS "outages" are inevitable...the whole system goes down for short periods of time every few years with solar activity, and local outages because of interference, solar or ionosphere weather, or just a fluke of bad satellite positioning, etc. Considering this, and with more and more people using digital solutions for their primary & backup, I think some safety features that make the app more useful without a lock is a good idea. IE, helping to cross-reference VORs, manually position the aircraft on the map, automatic dead-recokoning, could be useful in a pinch.