Every piece of compute in your system is one of two things. A service answers someone who is waiting. A worker does the job nobody is waiting for.
When a customer submits a payment, a service handles it, because the customer needs the answer now. The receipt email and the revenue sync go to workers, because no one is standing at the screen for them.
Get it wrong in one direction and the user waits on work they never needed to see. Get it wrong in the other and something they did need to see disappears into a queue.
If the user is waiting for it, it should not be a worker.
Kay
P.S. Course 0 is where these ideas become practice: https://systemthinkinglab.ai/course-0