I think mainly as a C replacement, for added productivity. Compared to Node.JS QuickJS seems to interoperate with C. Node.JS standard library is fully async, while QuickJS use C standard lib. There's also GnomeJS which can be used to build apps that looks and feels like native apps, maybe you can also do that with QuickJS!? Being able to obfuscate the code by compiling is also considered a feature, useful when you want to distribute an application without giving away the source code.