That helps with communicating the lat/long, but not with determining where that actually is. With what3words, not only are first responders still required to use some mobile device, but they're also reliant on a proprietary service (read: point of failure).
There should be no point of failure. By using the same hashing algorithm to produce 3 words worldwide, anyone with the same seed could produce coordinates for any words. Or the 3 words for any coordinates.
