If you already have Crystal Server or the BusinessObjects BI platform, look at its scheduling facilities first. SAP supports recurring report execution with parameters, database logon, output formats and destinations. Your edition, permissions and configured services determine the available choices.
A script is another route when a developer can maintain the report execution code and its runtime. Windows Task Scheduler can start that script; it does not render an RPT file by itself. Someone still owns export errors, credentials, changes to recipients and the days when the job runs late.
CRD is useful when those instructions need a dedicated home. A saved schedule can combine the dispatch report, its parameter values, PDF output, destination and reporting calendar. You keep the existing report and automate the work around it.
The CRD single-report guide shows those parts together.