I use Celtic modal/'dadgad' tuning because it immediately connects my creative output to the traditional music of my heritage.
But more importantly it releases me from confines of technical knowledge.
With a regularly tuned guitar, one finds oneself playing the same tired chord sequences and is bogged down by one's own musical learning.
Most of these songs have flowed quite naturally as a result of the way the guitar is tuned.
Melodies (mostly with a Celtic feel) emerge and lyrics seem to write themselves.
Even though many of my past projects have utilised an experimental indulgence, combined with a proficiency with technology, this music remains as 'traditional', acoustic, straight up and stripped down as possible.
Much of the lyrical content too is simple. The songs don't strive to be 'clever' or to speak a specific message beyond natural expression, they just are. And they are allowed to be - simple; naive; twee or stark.
I've been on Earth since 1977; into music since I can remember. Traded my tennis racket for a real guitar at age 11 or so and haven't looked back since.