Hello. Untill now, if we didn't want a parameter of a template to show the wikidata value but to show a different valuem we use the parameter name with the value we want (hand write). And if we wanted to show nothing in that parameter, we just add the name of the parameter without any value. Like |population= .
But the second function stop to work in Greek Wikipedia. For example, see w:el:Επαρχία Κερύνειας. The template show at population (πληθυσμός) "32 586 (1973)". But I had written to the template |πληθυσμός= . The template must show nothing.