Until the mid 20th century the Greek-Roman gods were usually referenced by their Roman names (planet names). More recently (Mighty Aphrodite, Poseidon Adventure) Greek names became more common. How and why the shift?
Not sure why specific films referenced Greek rather than Roman names, but possibly simply because they sounded better on the tongue. "Mighty Venus" doesn't sound quite as good, nor "The Neptune Adventure", which may have been confusing if people thought it a sci-fi film since it references a planet.
It may be precisely because the Roman names have been used previously that, in seeking to be slightly different, people moved more to the Greek. They do tend to sound classier, more snobbish in some regards, although that trend probably began with the romantics like Byron, and continued with Wilde.
It's also possible that it is to do with some pretty influential books focussing on the Greek deities written in the early to mid 20th century: Edith Hamilton's "
Mythology: Timeless Tales of Gods and Heroes" (1942) and D’Aulaires’ Book of Greek Myths (1967), a rather popular one among children, and Robert Graves' "
The Greek Myths" (1955).
FYI - the Classical pantheon was also originally two distinct pantheons, not just a renaming of the Greek gods into Roman names. E.g. Mars and Ares, while they both cover war, also cover different things from each other. And while Mars was a signifcant Roman god, Ares was somewhat less significant in the Greek pantheon. But over time they came to be merged until they pretty much came to be the same pantheon, just different names.