The only use of mediawiki/maps is the "_geo" data type, used in "Has coordinates" et al.
https://ropewiki.com/Property:Has_coordinates
We don't actually use it for maps. ¯\_(ツ)_/¯
It would be great to not need mediawiki/maps , as data-type/geo provides the underlying coordinate parsing.
However it's very hard to tell what features depend on this type (as it allows for proximity calculations and the like).
Having it installed doesn't do harm, it just confuses things.