I recognize that an accountant’s job is more than just running a bunch of calculations and getting a result. But part of the job is doing that, and it would be a real PITA if their calculator was stochastic. I would definitely not call it a productivity enhancer.
If my calculator sometimes returned incorrect results I would throw it out. And I say this as an MLE who builds neural nets.
You still make mistakes. Just because you did it yourself doesn't mean it's error free. The more complex the question the more error prone.
Thankfully the more complex the question almost always there's more than one way to derive the answer and you use that to check.