But seriously they aren't meaning "adult" as in "mature".
They are banking on three "adult" parameters based on the images:
- Lack of play time of adults → play anywhere in tabletop mode
The image is a busy adult in his hotel room with an impromptu play session (doesn't even have a TV set up).
- Having played the games when young → nostalgia
The image shows the adult on the right reminiscing playing the game as a teen next to (?) his girlfriend. He is the shaved head boy who's enthralled by the game in the flashback.
- Adults that might be new to gaming in general → the Switch is trendy for everyone
The image shows someone who see gaming ads but doesn't look like a typical gamer. The pensive woman on the right is the same as the woman looking at the ad in the center of the image. It has nothing to do with "otome games", it is simply juxtaposed with a "regular" corridor ad to show how "mainstream" gaming is becoming.
The images are a bit hard to read due to their use of juxtaposition of different angles without clear separation.
This is basically it, especially given Devil May Cry is in the packaging brand, which is targeted younger in Japan (despite the CERO ratings, it's often covered in children manga magazines in Japan).
Though I do have to wonder how Capcom Japan felt about DmC, though, given... some of the stuff in that game that conflicted with their demographics for the series.
Something to note that Resident Evil had a really odd demographic in Japan when they initially launched in Japan. The manuals all had furigana, including the packaging for the first two games, which is an indicator the games are intended to be accessible to all ages. Resident Evil was also covered in kids magazines, such as Coro Coro Comics, which is a magazine often read by and targeted towards younger elementary school kids. Same magazine that Super Mario-kun, Ratchet & Clank, Pokemon, Splatoon, and such were all serialized in.
Having said that, I'm not entirely sure when they started gearing towards older, because even aspects of Resident Evil 3 and Code: Veronica still had goofy and "shounen" elements to it, so hard to say. Nowadays, it's targeted towards Teens and Adults, though.
But yeah. The above poster basically hits all the right notes here. There's a very good chance we could see stuff, much like DMC, that has a much broader target demographic, and not strictly Mature stuff. But it's largely capitalizing on nostalgia and for Adults who have a difficult time finding some time to being able to play these games.
Given public commutes in Japan can be several hours sometimes, it's a perfect way for some Adults to be able to play some of this stuff, so... Honestly, really good marketing strategy.