I used to be able to rely on merfilly, but she finished her Big Damn Table and hasn't written the pairing since. She's all with the Slade/Dinah now. ;_;
Seems to be the prevailing opinion.
"Prevailing"? There are people who can't tell? But yeah, there's certainly just as much "this would never happen but it's hot so run with it" in smut fic as there is in the stereotypical porno (or, perhaps, less implausible sex, but between the implausible sex and the implausible emoporn and spilling and sharing of emotions, I'm sure it adds up to the same). I bet there's a whole study you could do there - certainly there's at least a metafandom conversation - about which people read and write stories with familiar characters (what if it's funny, what if they're In Space, what if they had sex), and which read and write familiar characters in new stories (they seem like they'd do this, so let's see it), and what kind of overlap there is. And, like, whether there's a correlation between people who do a lot of PWP and people who rarepair or AU or crackfic a lot, and how that correlates with OTPers.
So, lotta ground to cover before everything's beer and pizza.
Even the beer and pizza wouldn't be beer and pizza. The girls would want pineapple-anchovy or some shit that would totally baffle and disgust Dick, and Babs is totally a teetotaler and wouldn't have any booze in the house and would quietly and mostly not deliberately make Dick and Dinah feel really bad about bringing any around. It's just a disaster waiting to happen, really. ^^