You know, that never even occurred to me? Because despite being Christian, everything I know about saints' lives I got through doing work with paganism and magic: you can't seriously research pre-Christian beliefs in Western Europe without running into early saints' lives, because that's where things got preserved.

I mean, I know about St. Columba from three sources: cryptozoology books that quote the Loch Ness story; copyright history that talks about the copied psalter; and a book about pre-Christian Irish mythology that quotes some lines of verse attributed to him, in defense of preserving the old writings:
"If poet’s verses be but stories,
So be food and garments stories;
So is all the world a story;
So is man of dust a story."
(and then goes on to discuss how that poem supports comparison of early Irish cosmology with other mystical traditions such as Taoism and Sufism.)

I have almost no idea whether he has any relevance to Christianity (and honestly don't really care. :D)