Beautiful Irish or Scottish airs sound lovely when played plainly, often with little or no accompaniment, when played in sessions or other informal settings. In the first playthrough in that video the "beautiful" melody was pulled to pieces (I was scratching my head in places), rescued in later playthroughs by greater or lesser ornate accompaniment. It's an arrangement, a performance, lovely I'm sure on a record. I'm at a loss to see how it can be regarded as even vaguely Scottish-sounding. A very nice construction of one of my least favourite tunes, I thought. All just opinion from me.