Well - yes when looking at it it looks odd - but when I implemented the api and I looked at the API documentation at collmex it was super hard to find the matching fields (translate to german and find the right position).

The API is CSV based and thus the index is the most important criteria to feed it right.
When using the ruby API it gets so much easier to find and use the right fields. It just feels better to have the index in place and to be safe when using the API. The descriptive name makes it then just easier to read.