Hassling with it on Windows was always a big pain, with the versions being incompatible to one another. Also it left so much bloat and changed so many settings it looked like malware. But to be fair most of those crude media applications did that at this time. (Looking at you, Realplayer!)
Also you needed the browser (Internet Explorer) plugin, because HTML5 video wasn't a thing, but everyone wanted to display their media.
In a sidenote QuickTime also was part of other installers, too. One big CAD application needed QT on the system for displaying their help files (and I guess some media im-/export). It wouldn't even install without it. To make things worse, the installer itself – not the app, mind you – was in Java. To uninstall now you both need an old Java and an old QuickTime to be installed first...