Oghma served the Tuatha Dé Danann as their Champion, bringing his great strength to bear time and again in the challenges that faced his tribe. Yet it was not only the power of his arm by which he served. It was also with the power of his mind.
The creation of this script was as a proof of Ogma's own ingenuity and that the knowing of this should be kept for only the most learned to pursue the truths that the Ogham may reveal. The act of crafting ogham is one of capturing the very essence of a sound, which could also be said as the naming of a thing and binding it to a physical form.