We will never lose imperial measurements, as they are more human than metric. They are based on the size of part of the body like, hands, feets and palms, which can be used whilst crafting.
However, there is a lot of advantages to the metric system too. It is easier to go between millimetres, centimetres and meters than it is yards, inches and barleycorns.
A yard for example, is measured from the tip of your nose to the end of your outstrected arm. This is how cloth was measured, a cloth-yard being 37in.
A fathom is 2 yards, so a measure from hand to hand when both arms are stretched out.
We still use hands to correctly measure portion sizes. If for example, a child takes a hand full of nuts, that will be a smaller portion than an adult hand.
A length is the measurement of an object, whilst a distance is a measurement between two points. However, they are often interchangable despite being more associated with one or the another. For example, a bridge could be two miles in length and the distance travelled by someone crossing the bridge would also be 2 miles. Miles are more associated with distance but bigger things can be measured in miles.