What was the purpose of "indigo," something sought after by early colonists?

Early Colonists liked it because at that time, blue was a sought after color, and they had to seek a lot of the plants. It then became extremely popular because the color was so vibrant and dark. It was a very valuable export in the colonies.

Early colonists normally used it for a dye. They liked it because they didn't have to use a lot of it to colour the clothing or yarn or whatever they may be using it for.