The most interesting feature is the use of linear types to statically ensure sound usage of resources, including memory, in other words, no garbage collector.
It seems that when you do that, though, and especially from looking at the tutorial, you end up with semantics that are a) fundamentally different from GC-ed semantics, and b) explicit about memory management. But perhaps it amounts to a kind of type-safe memory management?
>>> Some people will argue that these are in fact "unique types" as opposed to "linear types", the difference being subtle (a unique type enforces that only ONE pointer exists at any given time, a linear type enforces that the amount of pointers is stable). However, you will often see unique types been called linear types in the litterature, and if P. Wadler can do it, so can I ! <<<