The script is not the problem, the queue is
Writing the automation is usually the easy part. An engineer who understands the problem can produce something that works in an afternoon, and for a while it does.
Then the rate card changes, or a supplier starts sending a different file, or a new exception appears that the original logic never anticipated. Now the change is a ticket, and it sits behind six things closer to the roadmap. The operations team, who understood exactly what needed to change, waits.
That is the real cost, and it recurs monthly. A tool that requires engineering to modify puts a permanent tax on a process whose rules change.
What happens when the author leaves
The second failure mode is quieter. Custom scripts accumulate logic that is only fully understood by whoever wrote it: a threshold chosen for a reason nobody recorded, a special case for one vendor, a dependency on a file path.
When that person changes role, the automation becomes a black box that still runs. Teams keep it going long past the point anyone is confident in it, because the alternative is reconstructing it from scratch. It also becomes a governance question — credentials nobody has reviewed, running somewhere nobody is monitoring.
Which one is right for your team
Write the script when the problem is well understood, unlikely to change, and you have engineering capacity that is genuinely free.
Choose Parabola when the rules change often, the process belongs to operations, and it needs to still be running — and still be understood — in two years.