This is the standard for composition or writing books for elementary school kids. It can also be a good choice for the elderly, for people who have large handwriting and people with visual impairment. It is also a good choice for 'casual' writing notebooks for teens.
This paper is recommended by some occupational therapists to help children space their letters correctly while handwriting. It may be particularly valuable for younger children learning to write or older children with IEPs (Individualized Education Plans).
French ruled paper was created by a librarian named Seyes in 1892 and is the standard writing paper in French high schools where it is used in a similar way to college rule in US schools.
It is also known as "Grands Carreaux" (large squares) paper or "Seyes" paper after its creator. The grid system helps children and teens form letters correctly.