Electronic computers were being built in WWII and television existed. I doubt many would see an iphone as magical.
The uneducated masses of soldiers and workers are much easier to dazzle and fool than technical personnel; and I apologize for not qualifying my previous comment enough to convey the idea that the Star Trek replicator, if it were to exist and be transported to the present day, would indeed be magic to any sane scientist or engineer.
Time Traveler: look at this iPhone!
WW2 soldier: that’s a flimsy looking walkie-talkie, wouldn’t last a day fighting the Waffen SS. Do you mind? I got work to do.
You could use it as a personal organizer - but without connectivity it can be argued that a paper organizer is easier to use. There are a few other programs that will also work in a fashion, but again lacking connectivity the paper equivalents are as good if not better.
There are also a few games that will work: you can really impress them with the games you can play.
The only thing impressive will be the camera - a full color picture that you can zoom in on and save is interesting. Having 10000 photos (plus some videos) in your pocket will get attention. Of course once the phone breaks you lose all that, but still it will be impressive.
You would also have no way to charge it, it’s not like any modern phone has simple inputs for 5v or whatever.
https://www.amazon.com/Best-Sellers-Cell-Phones-Accessories-...
That's a pretty low bar, isn't it? Show an iPhone's capabilities to, say, a WWII soldier or industrial revolution textile worker, and they'll deem it pretty magical.