Not doing something, or doing something dramatically simpler, ends up with less code being written. The cost of writing the code is usually a small fraction of the cost of supporting it during over the life span of the system.
One problem I faced was a client that as part of an e-commerce re-implementation brought a huge list of requirements for promotions and how they should work. There was hundreds of use-cases, some being very complicated.
I came back to the client and said, "are you sure you need all of this?" After working with them to investigate, it turned out that they had just documented all the features of their existing system. In the previous ten years, they had created exactly one coupon, and that was for a flat 10% off.
That was the functionality we initially went live with.
