The point of oversight
A trial result is a claim someone must answer for, and only a person or institution can be answerable. Oversight is what turns a fast output into a usable result.
Why traceability decides whether the saving survives
Automated steps are built so a reviewer can see which rules were applied and which records were used. If confirming the output is faster than producing it by hand, the time saving is real. If it is not, the saving disappears at the review desk.
Regulation as the condition for using the result
Rules about how trials are run, what must be recorded, and who must approve a result are what make a fast answer acceptable. A result produced outside those rules would be rejected, and a rejected result saves no time at all.