Background processing and regular processing are ultimately the same thing. It doesn't make sense to me why Heroku would try to price discriminate around that feature.
They don't. They both cost 5¢/hr per process. The only difference is, you get 1 'foreground' worker for free (per application), but not any 'background' workers.
The only difference is, you get 1 'foreground' worker for free
That's the differentiation.
BTW, don't get me wrong: Heroku is a standout service, and I use it as an example of how dramatically easier it is to start a technology business compared to even 10 years ago. I just have this little nitpicky complaint, that they ought to include one background process for free. The lack of it is actually blocking me from using Heroku for a startup idea at the moment. (I could always pay, sure, but when you're at the proof-of-concept stage, you're reluctant to put out even that much money.)