There are various words to express the concept of something or one being holy blessed or divine in Greek.
The two most people recall easily are adjectives derived Hiero- or Hagi- along with related verbs and nouns.
I was actually looking for which words Greek Classical or Koine uses for "temple" and while looking at the usage of hieron for temple once again pondered on its New Testament usage.
While both words are used hieron frequently means not just any temple but the one at Jerusalem with naos used for jewish n greek shrines and holy is more often hagios or hagia.
Part of the reason for hagios being a preferred usage seems to be its meaning holy and also often pure ?
A Temple in Greek is usually a Hieron holy thing or a Naos a dwelling place for a god separated from the mundane by a Temenos.
However other beings persons and places can be holy.
One notes the Holy Spirit is Hagia not Hiera but yet the Jerusalem Temple is Hieron and not Hagios.
I think another factor may be Hieros was seen as being more formal and literary than Hagios.
Plus the need to stress while there were many temples and shrines - naos there was only one Temple at Jerusalem.
Being hagios - holy for early Christians was not simply a privilege associated with temples and the Jerusalem elite. It was something you didnt have to go to Jerusalem to experience and acquire. Othere things a d places a d actions could be hallowed - hagizoo the verb from the hag root.
Anyway those are my opinions and thoughts on that subject.
Hopefully they are of som ed use to you?