It's all about what looks right - if you can wear a garment without any part of it attracting particular notice then you have it right.

I think that the low slung kilts are just about OK on someone thin, but with a loose shirt and no jacket they look untidy on anyone. There should be enough kilt to look right in proportion to the body wearing it, and hanging it at the right level can make the wearer look better.

Sometimes the high rise, particularly with a wide belt can be too much - they convert a normal kilt to something costume-y.

For everyone there will be a particular length and placing which is most flattering to their body shape, and (if worn) the width of belt and size of buckle will, if chosen properly, enhance the look.