I think you make light of the capability available in a Garmin portable GPS and an iPhone/iPad.
Having no exposure to either, I quite happily accept that they will do lots of useful and nice things.
Both will give you a moving map or flight instruments,
The map is fine, but tell me a bit more about the flight instruments. In particular, have you ever flown, under the hood, with all the aircraft instruments covered up, and then use, solely - as in nothing else, the portable flight instrument representation to maintain flight for an extended period of time ? That's the real world test and, if it doesn't work, where might that leave you in the event ..... ?
Not sure how I am going to lose everything in an electrical failure ... unless the panel is all electric.
In the typical heavy, when the ship's electrickery quits, you are back on the standby flight instruments ... until their batteries also quit .... then you are in the well-known situation of PYHBYLAKYAG. ANY sensible installation will have a similar arrangement, I suggest, as a (now retired) design signatory of many years' standing.
If you have some suck and blow flight instruments, that might be a saving grace, so long as you are not tangled up in icing conditions.
without independent battery powered AH and GPS
Usually, you would have standby power supplies to the emergency flight instruments ... but that only lasts for a while ....
I'm not trying to be a PITA here but, having a lot of IMC, night, and IFR flying in my history, this is a rather important consideration to follow through. It is my thought that many folks, not having tried their backup plans out in REALISTIC anger, may have unrealistic expectations of what is what ?
She said it was still fine and not to worry and to continue on
That's when you, as Captain Speaking and having just made the call, put it into action and turn around. I can still recall, as a young and newchum airline F/O, flying RM with the Type boss up to the property. I made some comment and was told, quite politely but firmly, "not even worth thinking about". That was, I suggest, the call you might make next time you find yourself in a like situation. The instructor was, no doubt, trying to achieve a training aim. That she made an unsatisfactory call is a problem but, I suggest, the main problem was sitting in your seat at the time. Again, as another anecdote, flying as a pretty senior B737 F/O, the captain, who was a mate of mind, made an observation to which I offered "you don't miss much". His response has always stayed with me - "I'm not allowed to". Same philosophy applies to bugsmashers as to airliners ?
Basically, I let her convince me that it was fine to continue.
Suckerbait stuff, that is.