It's bad because it obscures flow-of-control from the programmer and surrenders it to a large opaque system. In some cases it makes things a little bit easier,

It's bad because it obscures flow-of-control from the programmer and surrenders it to a large opaque system. In some cases it makes things a little bit easier, but when things go wrong it's a nightmare because your stack traces are no longer meaningful and flow of control is at arm's length and it's not easy to trace who's calling what. Not that it can't be handled well or used to good effect, but the idea of wandering into an unfamiliar FRP-based codebase which has been in the hands of multiple non-expert maintainers over a couple years is really the stuff of nightmares. edit: answering what's better Normal flow of control is better. You want to be able to look at a function, and see which functions are called from inside that function. And you want to be able to search all instances and see every place where a function is used. You don't want to have some black-box scheduler who's calling all your functions for you. That's how you end up with mysterious action at a distance, becuase you didn't know about the extra subscriber your colleague put on a publisher somewhere else in the codebase, or something strange happening because of an order-of-operations issue which is difficult to understand.