"chords in standard tuning can add too much harmonic information to modal tunes" That may seem "logical," but if so, many real folk musicians in Europe and America thought the "illogical" sounded good. In blues, for instance, the routine (and as far back as blues can be traced) use of I, IV, and V wasn't based on avoiding "too much" harmonic information relative to close to 1 2 b3 4 5 b7 at all, and similar is true of much European folk music.

Since this quotes me, I'll respond. I never used the word 'logical', and stressed that this was simply my own taste. I find the rest of the comment difficult to understand. I'm not sure which 'real folk musicians in Europe' you're referring to, but my area is English folk song in which the tradition is unaccompanied vocal - so to accompany it requires that questions of appropriateness and taste are addressed. Different musicians have different solutions.