What3Words is not a tracking application. It's more akin to your latitude and longitude, except the location is expressed using words as the coordinates rather than numbers. So if I want to tell you that I am at ///hitch.member.embodied (I'm not, but I wish I were!) I can tell you that.

If you are thinking of "Glympse" rather than "What3Words", then Glympse is indeed a tracking application. Your location is communicated to their servers, and from there, others can access it via a unique link. How well that link is protected and kept private, I don't know. I would say generically, if your concerned about privacy to that degree, you wouldn't be a candidate to use a tracking app, any tracking app, in the first place.