You might have been able to use the same syntax before, but writing code for Reason native was already very different to writing Reason+BuckleScript for the bro

You might have been able to use the same syntax before, but writing code for Reason native was already very different to writing Reason+BuckleScript for the browser. This just formalises the split. To write the same code for both front and back end js_of_ocaml has been the standard since long before Reason came along, and it works just fine with Reason native.