issue_comments: 249435537

why make it the new default instead of using a keyword (something like no_index=True)?

Basically, this is about the user experience and first impressions.

There are very few cases when somebody would prefer a default index to no index at all, so I see few cases for no_index=False in the long term. It seems cleaner to simply spell this as coords={'x': range(n)}.

From the experience of new users, it's really nice to be able to incrementally try out features from a new library. Seeing extra information appear in the data model that they didn't add makes people (rightfully) nervous, because they don't know how it will work yet.

without coordinates the majority of xarray's functions are not working anymore. So what will xarray have that numpy doesn't have already? (the only thing I could think of is labeled dimensions, but there are probably more use cases?)

Labeled dimensions without coordinate labels actually get you plenty. You get better broadcasting, aggregation (e.g., .sum('x')) and even indexing (e.g., .isel(x=0)).

But the big advantage is the ability to cleanly mix dimensions with and without indexes on the same objects, which covers several more use cases for labeled arrays. Examples off hand include images (see the example from my first post) and machine learning models (where columns usually have labels corresponding to features but rows often are simply unlabeled examples).