This is exactly it- the required pressure to write. Fountain pens are effortless in marking, and flow. This leads also naturally to flowing cursive text. While

This is exactly it- the required pressure to write. Fountain pens are effortless in marking, and flow. This leads also naturally to flowing cursive text. While I love fine liners, ball points or gel pens, few write like a fountain pen (and the ones that do are called fountain pen like).