from barter and now using paper money, there is a reason for a change and innoovation, from classical novel to modern novel there is a different in how the story told, simply said for anime and manga there is a reason for it called fan-service:"Fan service (ファンサービス, fan sābisu), fanservice or service cut (サービスカット, sābisu katto), is material in a work of fiction or in a fictional series which is intentionally added to please the audience, often sexual in nature, such as nudity.(wikipedia)" especially for generic fiction.

fun fun fun, no sternous thingking,,, laugh al the way..... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... okay.