You might be over-analysing what Minjo is saying, perhaps. He might simply be amazed that "yaoi"-style dating-genre ero-VN-games exist, rather than simply that visual novels (as a medium) exist.
Visual novels, as a much more broad gaming genre have a lot of popular examples, already...the
Phoenix Wright series by CAPCOM is a visual novel with crime/mystery/courtroom intrigue plot elements and mini-games. On the other side of the (popular) spectrum, one could argue that
Dragon Age and
Mass Effect series are, at their core, life/dating sims with fantasy/sci-fi RPG/FPS/3PS-mission gaming elements attached onto the main plotline (and even gay/lesbian romances possible.)
Of course the sheer bulk of het ero-game dating sims (as a sub-genre) represent the majority of examples on the spectrum of VN-games, but the niche yaoi/otome/yuri genres have a following, even among the indie developers outside Japan.
I personally adore VN's in general, and dating sims/life sims as a sub-genre. As a hopeless romantic, I really like seeing charas I like getting together (whether in a 'chaste' storyline or 'ero'/H-style story) as I would watching fun romantic comedies or dramas.
At their worst, such games come across as amateurish fan-fictions. But when a well-written script, punchy dialogue, appealing art-style, and a touching background track all come together, VN's can border on epic high-art. ^^ I've personally had satisfying catharses and epiphany-inspiring changes of perspective just from playing well-written VN games. :)
And quite a lot of them, being indie-developed, are either free or have free-demos available on their dev websites. ^^