One thing (which is mentioned in the wikipedia page) is that in the metric system where e.g. meters and kilometers are related by a power of 10, a length which is a preferred number in one unit will also be a preferred number in the other unit. This does not work out for e.g. feet and miles.

So imagine you have a landscape architect designing the interior of a park and a civil engineer designing the city around it. In the metric system, their preferred placements automatically agree. In imperial units they have to coordinate that.