Graphics performance is a huge upgrade. Playing Battlefield and Call of Duty on my PS4 Pro would shudder to a halt when faced with high graphic demands, the PS5 is buttery smooth. Nevermind the frame rate advantage on the PS5.
Controllers is a big plus, though they are heavier, and more expensive to replace.
Generally everything runs faster, from turning on the machine to loading games and cut scenes. It all adds up. BF2042 for example loads up almost immediately on a PS5, where it would take over a minute on a PS4.
Immeasurably upgraded experience compared to the PS4. And you know the console will be around for the next 5-10 years in terms of support and new games.