The a superhero like Superman becoming a parent is a natural evolution of the character.
Superman, Batman and the Flash were all famous loners in that they often did their best work by themselves. Batman and Flash had multiple sidekicks, but writers always found a way to remove them from the picture (either by having the sidekick "graduate" to their own superhero name or tragically kill the sidekick, as was the case with Jason Todd in Batman: Death in the Family). Now in 2022, all three have children: Superman has Jonathan Kent, Batman has Damian Wayne, and the Flash has Iris and Jai. All four children have inherited their parents' powers and/or skills...and this is where the true genius of portraying a superhero as a parent comes in.
The parenting methods of each superhero are radically different. Superman is by and large the perfect father; he's always there for his family while also helping others. Jonathan Kent has all the powers of Superman and the moral center to use those powers for the good of all humankind. He may be a tad more impatient than Clark Kent, but the latter teaches the former though saving the day together. When Clark leaves Earth, he knows through those sessions that his son is ready to carry on the work as the planet's new Superman. Wally West's approach to being a parent is considerably more scattershot.
Iris is younger than Jonathan, and delights in toeing the line with her father, testing just how many rules she can break while also poking holes in her father's logic regarding his instructions. One can imagine the difficulties of parenting a child with all the powers of the Speed Force and none of the restraint and experience that Wally has accumulated throughout his years as a crimefighter. As for Batman's son, Damian Wayne wasn't raised by Bruce at all; the two met when Damian was seven. Over time, the two bonded and though Damian may occasionally obey Bruce begrudgingly, he nevertheless respects and even ires his father.
The DC superheroes - primarily those of the Justice League - have a reputation for being incredibly overpowered and/or prepared to the point of prescience. This makes them problematic in of relatability; Jon, Damian and Iris and Jai help ground these superheroes in a remarkable way. When superheroes become parents and deal with all the associated challenges, the characters - and the DC Comics Universe as a whole - benefit.
