The WFRA complete ban is in contrast to the (English) FRA revised policy where individual organisers can decide to allow GPS or not. And on those events which proscribe the use of GPS, a runner is at liberty to carry one. But if used, perhaps in an emergency or for any reason, that runner is required to declare themselves non-competitive.
Navigation when cycling long distances is a skill but a lower level of expertise is required where a GPS with a loaded track/route is available/used. Use of GPS devices mean riders seem (to me) to be far less aware of where they are, where they're going and how far it is. And reacting to changes eg GPS goes down or a road is closed, is often much easier (if the expertise has been developed) with a carried paper map. The seasoned navigator (that's me, with or without GPS, who nevertheless still gets miswayd) with their paper map and route preparation in the bag, can do what they do well and be happy to be of service to those who wish to follow.