Growable stacks have been around for decades, it's far away from research language territory.

The real benefit is not to handle the worst case/OOM condition that a big enough callstack gives you. It's to make the default stack size much, much smaller for the common case where you don't need it at all (or want to shrink it later). Growable stacks use less memory on average than your typical embedded device because they can start in the dozens of bytes, instead of requiring kilo/mega bytes of stack space (allocated, not just reserved). It's kinda the only way you can make a runtime scale to millions of concurrent call stacks.