Why isn't Raku Ichijou's mother's face ever revealed in the manga? Why isn't Raku Ichijou's mother's face ever revealed in the manga?

I mean, the manga ended, and she was the last character introduced in the series. What was the need to hide her face then?
Maybe because she wasn't integral to the story in any manner.

For instance we only see Midoriya's mother in My Hero Academia there is no mention of his father except in some throwaway scenes. 

It may be due to the fact that drawing Manga is a tedious job and author might want to keep his work as easy as possible and it's much simpler by minimising the characters introduced.