Having been bombarded with w3w adverts, mainly on YouTube, I was pondering whether w3w was really that useful, at a casual glance it seems like a good idea. I also wondered how closed it was as a standard, and found it looked entirely proprietary and secret.
A bit more searching and I found this blog, confirming my suspicions.
I can’t see why someone wouldn’t simply open Google maps, say, and share their last/long location in a text message. I’ve done that, it’s easy, and no transcription errors, and SMS messages will often get through when signals too weak for voice calls.