Z Accelerators are essential when the data volumes are so large that the processing time to run your reports is unacceptable. If you are able to write a report that runs within acceptable time-constraints then the use of Z Accelerators may not be required. However, even if your report runs within 2 hours (and this is considered acceptable) you are still able to use Z Accelerators to bring this run-time down even further.
It is our consideration that almost any report that executes in the background can gain from being run using Z Accelerators. This is because the Z Accelerator format not only promotes performance improvements, but also cost reductions in maintenance by having a generic format. It also provides the benefit of separating the processing and presentation logic. Separate presentation logic allows the data to be viewed interactively and in a user-friendly manner – far easier than lengthy static list output.