I would imagine the differences would be the same as the differences
between non-explicit podfic and non-explicit audiobooks, that is to say,
the one big difference is that audiobooks tend to be a little cleaner,
because they're recorded in studios and there's at least one other person
checking for gaffes, and they're much more consistent about using different
voices/ways of speaking for different characters. I think this is because a
lot of audiobook readers are also actors, so they approach it as an acting
job instead of a recounting a story job. But that's my just so story in my
head, I could be wrong.
Also, I suspect that readers who are concerned enough about erotica to use
a pseudonym are not so concerned about the people who are listening to the
erotica audiobook long enough to identify them, they're concerned about the
people doing a web search on their name and not wanting to cast them as
grandma in a movie because they've done porn.