Being close to a or being a domain expert yourself isn't enough. Most domain experts don't know the domain well enough to automate solutions for it, you need a

Being close to a or being a domain expert yourself isn't enough. Most domain experts don't know the domain well enough to automate solutions for it, you need a much better understanding to program than to do it yourself. So most domain experts will come up with very bad rules for the programmers to implement, and those rules are buggy even when implemented correctly since the domain experts didn't think of everything.