Technically it's also a toy because it tries to do async without the right primitives built into the language. Hence the async spaghetti (the 2010's GOTO), and

Technically it's also a toy because it tries to do async without the right primitives built into the language. Hence the async spaghetti (the 2010's GOTO), and other limitations. It might prevail in a "worse is better" way, because of popularity, but technologically it should be replaced by a better language/framework combo.