I’m going to go all contrarian like Evangelos Lolos did. Way too much antiquity here.
Special shoutout to John Salaris, who also went with two overtly modern names: Panagiota (Greek equivalent of Madonna), and Argyro “Silver”.
Those names ending in –o are particularly delicious. If they aren’t truncations of other names (Βαγγελιώ < Evangeline, Βαλάντω < Chrysovalantes, Δέσπω < Despina, Λενιώ < Helen), they are often names of precious substances or things, suffixed with an –o: Αστέρω “Star”, Διαμάντω “Diamond”, Κρυστάλλω “Crystal”, Ζαφείρω “Sapphire”, Ζαχάρω “Sugar”.
Greeks like to tell themselves they are a continuation of Ancient Greek names like Sappho. Hence spelling them with an omega. But if they were, they wouldn’t sound so decidedly hayseed, and be snobbed off by so many Greeks.
The likeliest derivation of that -o? No surprise there. Slavonic vocatives; cf. Bulgarian babo “grandmother (vocative)”, which has been borrowed into Greek as μπάμπω.
Yes, they’re a contrarian choice. But I still think they are charming.