You can marry an anime waifu or another fictitious 3D figure, whether or not they are human. The only restriction is that the spouse may only apply once, and it cannot be to a real person. Of course, there are anime fans who would happily date and marry their waifu. There was a case in Japan where two people married their respective virtual girlfriends from "Lovely Planet 5" because they thought it was legal marriage. The court ruled that since both parties understood the relationship wasn't real, it wasn't illegal marriage. There have been other cases like this one across Japan. It's not uncommon for Japanese gamers to marry their virtual partners. Anime girls tend to be popular among Japanese boys because they look cute and also because marrying your girlfriend allows you to rule the house (unless you want to share your wife with others). Geeks who marry their virtual girlfriends usually do so because they can't find any real women who love them. In conclusion, anime girls are great because you can marry them and also because they look cute.