The page contains the passage "This extension adds a new parser function, {{#coordinates:}}, that saves coordinates to the database. Function's input format is made as compatible as possible with GeoHack"
I don't understand what database is being referred to. Does it mean WikiData? Does adding coordinates to a Wikipedia article add the coordinates to WikiData? (That seems unlikely.)
Also, there is a conflict between WIkiData and this page. WikiData Wikibase/DataModel has a precision field. It is not defined exactly what this represents, but the normal interpretation by a person with a technical background would be the uncertainty in the measurement process that produced the latitude and longitude. The DataModel used to have a dimension field, but that was deleted in March. This page has a dimension parameter.
The problem is that depending on the object and measurement method, we could have a large object with a point within it that has been precisely determined (e.g. the Washington Monument) or we could have a tiny object who's position has not been precisely determined (e.g. the Airy transit circle at the Royal Observatory, Greenwich).