I have been listening to "Celtic" bands a long time, and guitar players should be aware of what they are doing. (The guitar was never used in Irish and Scottish (I & S) music until recently, when American bands made it seem that no band was complete without them.)

The I & S bands tuned the guitars in DADGAB because the notes go well with all the dance music they play in D and G. Then they reduced the guitar to a percussion instrument. I have listened to recording after recording where the guitar simply goes "brang brangety brang" as if it were drum.

(Meanwhile, the Irish took their drum, the bodhran, and played it in such a complex and melodious manner that it became more of a melody instrument than a percussion instrument.)

I think that this kind of playing has its place, but people who love their guitars should realize that the instrument is diminished in the process.