Why are the seven deadly sins used so often in anime? Pretty much as my question states itself. Why are the seven deadly sins used so often?

In a lot of anime I have watched/re-watched, lately I notice either a reference to the 7 deadly sins or their use. For example, in anime like Full Metal Alchemist and Soul Eater, these 7 sins are referenced as an obstacle to bypass or enemies to overcome.

Is there a specific reason for this? Or is this a reference of them being beyond sin?
From my English composition class - its easier to write a story around a theme.
I don't think stories that use the seven deadly sins are more prevalant in Anime, its just that we are talking about eastern entertainment using western themes, which naturally calls more attention to itself.
As far as there being any significant message in the theme of the seven deadly sins. To me, the works just use the seven deadly sins because they are universally recognizable.

The most common contemporary understanding of theme is an idea or point that is central to a story, which can often be summed in a single word (e.g. love, death, betrayal). Typical examples of themes of this type are conflict between the individual and society; coming of age; humans in conflict with technology; nostalgia; and the dangers of unchecked ambition. A theme may be exemplified by the actions, utterances, or thoughts of a character in a novel. An example of this would be the theme loneliness in John Steinbeck's Of Mice and Men, wherein many of the characters seem to be lonely. It may differ from the thesis—the text's or author's implied worldview.
A story may have several themes. Themes often explore historically common or cross-culturally recognizable ideas, such as ethical questions, and are usually implied rather than stated explicitly. An example of this would be whether one should live a seemingly better life, at the price of giving up parts of one's humanity, which is a theme in Aldous Huxley’s Brave New World. Along with plot, character, setting, and style, theme is considered one of the components of fiction. - Wikipedia