The AI taxonomy includes the term "Expert Systems" for these kinds of things. On the one hand it's definitely not of the new wave of ML AI so hyping those things as innovative is off. On the other hand we should definitely give more attention to that kind of setup and understand how to build/maintain/test it properly. Otherwise often it ends up being ran by a few hundred Excel sheets and a few severely underpaid people and that's a disaster waiting to happen. The AS400->VB6->NewShiny path actually sounds like a success case given the messes that are out there.
Often the biggest benefit is that the ML version is good at catching when the experts hadn't had their cup of coffee as well.
Most experts are like family doctors, they get the correct diagnosis 70% of the time. And even if you juice them up real good, they will ALWAYS lose 5% to human error.
The ML also hits the 70% mark, but it's a different 70%, so it'll fix 70% of the errors. Then you're batting at 0.91 instead of 0.70.
