Some apps make this easier than others, with Google Maps still a mystery. In an emergency, or if I really needed a try location, I'd feel more comfortable with the dirt-simple nature of w3w then remembering how to find the lat/long and copying or saying all the digits (there are a lot of them!)
Apple Maps surprised me by being the easiest. It shows lat/long under the "My Location" pane which appears when I tap the blue dot. They make it easy to copy /paste.
Google Maps on iOS replaces that with a "Plus code". I can't find where my lat/long is in this thing, and gave up. (Hints and Spoilers welcome!)
Over the years, I have tried other map apps which I pulled up to see how they handled lat/long:
* Maps.me acts similarly to Apple Maps, tap the blue dot.
* Here We Go maps makes you drop a pin at your location, but then displays lat/long. Magic Earth has same problem/approach. Who would remember how to do that in a rush?
* Organic Maps over engineered this one: tap the blue arrow and lat/long appears, but when you tap it to copy, it changes to a new format each time (no commas, an alph-numeric I don't know, a url, a UTM, an MGRS, and then back to lat/long). Turns out you can press and hold to get a copy menu.
* Google Earth displays the lat/long right on the screen... But it's not copyable.
W3w may have implementation problems, but it does a great start on simplifying the answer to a verbal "where are you?". The rest of these, esp Google Maps, just aren't quite there yet.