Short answers, pulled from the story.
The earliest inscribed objects bearing Greek letters date from the late 9th or early 8th century BC. The oldest substantial examples like the Dipylon vase and the cup of Nestor appear around 750 BC.
Herodotus recorded that the Phoenicians who arrived with Cadmus brought the alphabet into Hellas. This event transformed a consonant-only system into the first true alphabet capable of writing vowels.
In 403 BC, at the suggestion of the archon Eucleides, the Athenian Assembly formally abandoned the Old Attic alphabet and adopted the Ionian alphabet. This standardization became known as the Eucleidean alphabet and displaced local alphabets across the Greek-speaking world by the end of the 4th century BC.
In May 2021, the World Health Organization announced that the variants of SARS-CoV-2 of the virus would be named using letters of the Greek alphabet. This decision aimed to avoid stigma and simplify communications for non-scientific audiences.
The two principal encodings still used today are ISO/IEC 8859-7 and Unicode. ISO 8859-7 supports only the monotonic orthography, while Unicode supports both the monotonic and polytonic orthographies.