It was marketed for a long time to use primarily for Java applets. Moreover, it was marketed as if "old sucking java applets was replaced with javafx", in reality it replaced Swing in applets, not applets. Then, for some period of time, it was marketed as kiosks platform.

I didn't know that it's just a GUI toolkit until recent time when someone told me so. Its website still not says anything sane, what it is. "client application platform for desktop, mobile and embedded systems built on Java". Well, Java itself is application platform for desktop and whatever apps.