While now and for past thousands of years these terraces were made as rice terraces - the same also could be used for any kind of terrace agriculture
Steep mountains may be unfit for agriculture. Once converted into terraces, anything could be planted beside rice. Agriculture terraces are easier to irrigate, to plant and to harvest. The work to create such agriculture terraces however always remains the same. Heavy work that needs to be done by hand - centuries of ongoing work resulting in agriculture harvest during thousands of years to come.