Why can an arbitrary IEnumerable<string> not be matched directly with ["run", var file]?

Why can an arbitrary IEnumerable<string> not be matched directly with ["run", var file]?

1. List patterns require a count and an indexer; IEnumerable only promises enumeration.
2. List patterns accept numeric elements only.
3. A list pattern always mutates its input.
4. The syntax is limited to collection expressions.