I HAVE to believe that people who play these things have no desire to come at them from a role-playing perspective. When I see something that is the cross between an earth elemental and a mortal, the roleplayer in me dies a little bit.
Then I'd have to believe, no disrespect intended, that your horizons are a bit narrow. IME,
while its true that there are players who are just looking for statistical advangages, they tend to do that with EVERY PC concept they have. But not everyone is like that...
There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy. William Shakespeare, "Hamlet", Act 1 scene 5
I've been an RPGer for 28 years. I've played all of the core races and classes. I've also played more than just D&D. My reading is also not limited to Tolkien, Lieber, Moorcock, Howard and Vance...or even to sci-fi and fantasy. If you read enough, you'll find characters who are part elemental (or demon, or devil, or dragon, or angel, or...).
Sometimes...
many times...a player is just looking for something different. Sometimes they ask themselves what it would be like to "flip the script" and play the other side of a classic story.
Take the
Beowulf story, for instance. Aside from the original telling, I've read it as a sci-fi story (Niven & Pournelle), a semi-historical story (Creighton), with additional players (Xena TV show), and 2 different stories from Grendel's and his Mother's viewpoints (don't recall who wrote those). Each retelling put a different spin on things.
Some of my PC concepts are sci-fi or superheroic or pulp archetypes ported into fantasy...and vice versa.
I had a human Ranger based on Batman...and another Gnomish one based on the Lone Ranger (down to his Giant Space Hamster steed, "Mithril").
When I played a Minotaur Ftr/MU in 2Ed, it was because I was playing the "Chosen One" archetype from a different angle.
When I played a Drow Druid/Rgr/MU in 1Ed (years before whats-his name), it was because I was playing the "Outsider" archetype.
The background of a 2Ed Drow MU/Th I once played asked the (still unanswered question) whether she was an insane drow or a LARP robot somehow ported into a world in which magic worked.
My current Githzerai Monk/PsiWar/Lucid Cenobite is a "Stranger in a strange land," not unlike Kwai Chang Caine of
Kung Fu fame.
My current Human Rgr/Ftr/Diviner/Spellsword is based on
Indiana Jones.
In modern/supers games, the rping is excellent, as everyone is human (or near human) and personality and motivation is easily cultivated in a familiar environment.
Then you're missing out on the fun of playing aliens.
Among my past supers PCs, I have a 7' tall silvery humanoid gladiator from a matriarchal society who must consume her body weight in food daily (and not everything on the planet agrees with her digestive system), a 3' diameter disembodied ball of energy contained within its spaceship, and a collective entity that resembles a protean bundle of 6cm diameter metallically coated carbon-fiber coils from a Jovian world (based on something from a Greg Bear novel).