I don't really like W3W (with one exception - see below) because of their business model. Free of charge is the bit to convert a location to W3W - potentially chargable is the conversion of W3W to a position. At a moments notice they could say to Amazon, Emergency Services, DPD etc "20p a lookup". Also, there are examples above of two locations having similar words - it's OK saying "oh, you know it's wrong because it's in the wrong country" but that doesn't help work out which word is wrong.
For emergency calls - if the phone knows where it is (and if it doesn't, W3W won't work either) the handset sends a silent text to 999 with Lat, Long, Altitude and precision. It's part of the phone operating system whether Google, Android or iOS. https://en.wikipedia.org/wiki/Advanced_Mobile_Location. All Blue light services in the UK have access to the callers location in this way - but some prefer to stick with W3W, Postcodes or whatever
If you want to share your location with a friend, most messaging Apps have a single keypress to share either current location or a continuously updated location. WhatsApp and Signal certainly do.
The exception is where you can't (for whatever reason) call from the location you want to give - for example someone slips on the towpath but there is no mobile signal. Someone could note the W3W, walk to where there was a signal, call for help and make it clear "not where I'm phoning from but What.Three.Words"