The ski jump allows the aircraft to get airborne with a greater take off weight, than a STOVL jet would do from a flat deck.
It’s vastly more capable compared to something like the USS America.
Substance over style, every time.
It doesn’t make sense not to put ski jumps on the America class, other than they want to deliberately degrade their capability so that congress cuts funding for super carriers and uses the amphibious assault ships with Harriers/F35Bs instead.