"What power lies in a name? Gwernin Kyuarwyd am I, Gwernin Storyteller. So have I said before. And yet I practice all the bardic arts, so far as I am able – poetry and song and harping, as well as story-telling and the recitation of lore. So why do I call myself Gwernin Kyuarwyd, Gwernin Storyteller, and not Gwernin Fardd, Gwernin the Bard?" -Gwernin, in Storyteller
In early Wales, as I indicated in a previous post, bards might - among other things - be storytellers, but storytellers were not necessarily bards. True, their services were valued, but they were not on the same social level as the men of art, and there is no sign, even in the Irish laws, that they were regulated in the same way. It was a niche an aspiring young man might fill, while hoping for a chance to do better.
In historical fiction, and especially in fantasy, if a traveling entertainer is involved in the story, he (or sometimes she) is usually a bard or harper. These, by the way, are not the same, and there are some grounds for doubting that the harp in its modern form was even present in 6th century Britain and Ireland. However, some archetypes are too deeply engrained to dislodge, and I have allowed my bards to keep their harps, whether justified or not!
Why have a storyteller for my narrator? Partly because at the time I started the monthly column which eventually became a book, I felt myself, like Gwernin, to be a storyteller, but not yet a bard. And partly because ... that's just how it happened! As to why, in the quote above, Gwernin declines to so describe himself, even after meeting the qualifications ... well, for that answer, you'll have to read the book.
Or wait for another day.