I remember clicking around that application as a kid trying to figure out what was good about it. I never figured it out. Seeing the splash because it decided it was the default application for some random format was always annoying. But back then you kind of kept everything around just in case - sometimes nothing could play a file except for real player so you’d begrudgingly let it play it for you.

Another one that died silently is Winamp. Oh man, I still remember those funky Winamp skins from the early 2000s.

VLC still supports some RealPlayer files. I have a few hundred rips of 1920s vinyl in RP format that I can still play that way, but I'm not sure if all codecs would be supported.