My understanding is that the difference between 0-indexing and 1-indexing manifests in algorithms which iterate over a list. If the start of a list is at index 0, the end is at index "length - 1" and if the start of a list is at index 1, the end is at index "length". Neither fundamentally changes such algorithms.
That's why it's so low on the list of importance when considering language features; it doesn't fundamentally change what the language does or how it's organized (perhaps beyond some contrived examples) and instead only affects what the code looks like.