Screensavers are a lost art. I still enjoy them, but at some point we just gave up on them. In the era of CRTs they had a practical purpose (they're screen savers, after all), but modern OLED displays also suffer from burn-in for which screensavers would be useful. My enjoyment is purely aesthetic, though. Sometimes I just want to have something pleasing to glance at in the background, instead of a black screen.
Nowadays most operating systems and desktop environments don't even support them. The state of the art on Linux still seems to be `xscreensaver`, which does have many great ones, but the collection is static, and most of it is visually stuck in the 90s. I wouldn't even try getting it to run on Wayland, and when I last looked into it, it required some hacks and 3rd-party tools.
Also, I've always found the feature of screen locking and screen saving to be orthogonal. Often I want to see pretty graphics without locking my screen, and viceversa.