Specifically structural record types, and many statically typed languages don't have them. (not Java, not C++, not Haskell, not Rust, yes Swift, yes OCaml)
What are interesting use cases for more dynamic (i.e. non-fixed set of keys / types)?
I mean, if you need something super-abstract and flexible, you are unlikely to need a built-in convenient syntax to hardcode such values.
For those new to this, good search terms are "row polymorphism", "extensible records", and "polymorphic variants".