This isn’t the first time this approach has been taken either with the character.
CW’s The Flash TV series also did a Flashpoint episode and it too took cues from Back to the Future, as well as Terminator and Groundhog Day.
Using Back to the Future as a touchstone isn’t a bad idea either, and it’s a lofty thing to aspire to, as that film did fun, entertaining time travel with real stakes as well as any movie has ever done.
This isn’t an entirely unexpected change, as DC seems to want to make its DCEU shared universe more akin to Marvel’s with a more lighthearted tone while using a potential sub-label, ‘DC Dark’ or ‘DC Black’ to push standalone, grittier tales like the Joker origin film.