Storytelling has a multifaceted history of use including, education of both children and adults, history keeping, law making, conflict resolution, community decision-making and mental healing. Many of these uses are still applied by tellers today.
As such, storytellers were (up until the last 300 years) members of the elite class in many cultures including Celtic, where Brehons / Bards / Seanachaidhean / Storytellers were valuable advisors to the Clan Chiefs and leaders. The Scottish tradition comes from our Irish ancestry. Tales and the culture were brought over in around 500AD with the Irish invasion. That said, there is something common to the storytelling from all the Celtic nations.