Well this is analogous to the horizontal stroke through the middle that is sometimes used in handwriting in the Western world but which is almost never used in computer fonts.
7 is my favourite lucky number! Neat! Have you heard of how the Hindus wrote the number 7? It was more like an upside-down J. Really? What other cultures have history with the letter? Well, the western Ghubar Arabs' main contribution was to make the longer line diagonal rather than straight, though they showed some tendencies to making the character more rectilinear. Cool! I always wondered why the letter looked the way it did!
This is analogous to the horizontal stroke through the middle that is sometimes used in handwriting in the Western world but which is almost never used in computer fonts.