The first thing a Dex Developer would do once he/she learns Dex programming is to start becoming curious and write their own functions / procedures to meet the requirements.
I am certainly not against it and I myself started off my programming career like that. But we must also understand that when we have in-built functions that can do what we want, we don’t have to lose our time in recreating the same logic.
RW_DateToString function would certainly save us lot of time. And it does have almost all much used formats to display a Date on the report.
David details this function in his article: Display Dates in Any Format On Report.