Consider the scenario.
There is a Job with the "Start" step. Multiple transformations are connected to the Start step.
Unless specified, these steps will execute in the sequence they are attached to the "Start" step.
The customer wants the UI to number then accordingly. This will make it very easy to understand the sequence in which they will be executed. This is a "interaction design" or "user usability" issue. Perhaps having the UI number the steps and show that on the screen would have made it more intuitive.