The specific artwork "Such a Sharp Pain" is sought after due to its aesthetic quality. While the specific visual details vary based on the artist's current portfolio (and specific character focus), the title suggests a theme of emotional or physical intensity, which is a common draw for collectors of digital illustration.
Most plausibly, wa is a in a command string meant to be wa for “wallpaper” or “ward” (as in memory ward). Or it could be the last two characters of an incomplete code: unlock_wa_02 . such+a+sharp+pain+v011rsp+gallery+unlock+wa