Its just too strong. The development loop is great when using a build chain like gulp, deployment is relatively easy, scaling up and out is easy (by nature of it being a static webapp), single toolchain, single language (well at its core anyway) etc etc.

Writing API's, specifically restful ones, can be done, and for small stuff its quite nice, but as soon as you start adding processes, services and anything more complex than crud functionality it falls over development wise.