I suspect decisions trees are still highly under utilized for optimizing any human in the loop processes that require an actual script that a person needs to follow.

It's not an uncommon problem that you're faced with needing to make a series of decisions in a business environment and old-school decision trees give a remarkably clear, readable output of the optimal way to make these decisions in as few choices as possible.

Any data scientists working on teams with call centers, sales teams or customer support people would likely find a surprisingly useful application of this mostly forgotten (other than a building block for RFs) tool.