It seems that Etak was to navigation systems what Jodorowsky's Dune was to 1980s sci-fi: a trail blazing endeavour that was wild and wildly innovative, did not fulfill its intended mission but rather set up an entire field for subsequent success.
Also: the design must have included several masterpieces when considering the state of tech in the 1980s: even seeking to the right point on the map cassette is an untrivially hard problem.