I can understand your confusion, since you're conflating applications with the desktop. I started out on GNOME, but moved to KDE back when it was at version 1.44. I found the desktop look and feel to be vastly more pleasing than GNOME, Konqueror to be tremendously more functional and polished than whatever GNOME was using at the time, and KDE's customizability to be worlds more advanced than GNOME.
I absolutely love all of Plasma's bells and whistles, and get quite annoyed when they crash. One of my favorite little plasmoids is the calculator in krunner. It's so handy to have a line-based calculator a simple Alt-F2 away. And KWin's desktop effects are so well integrated into the desktop that it's painful to sit down at any desktop that doesn't have them.
As far as applications, I run Konqueror for my file manager but not as a Web browser; as a Web browser, it is far behind Firefox and Chrome. But as a file manager, it's top-notch. It's castrated cousin, Dolphin, is an abomination that should have been stillborn.
I run LibreOffice, as it is the crown jewel of office suites for Linux, obviously.
K9 was the best, simplest DVD copying utility I've ever used; it's a shame it was abandoned. I have yet to find anything to fill its shoes.
KTorrent is a fantastic bit torrent client.
I could go on, but I won't. For me, KDE's customizability is a huge plus that puts everything else to shame. And it has many applications that I consider to be best-of-class. It fits my workflow better than any other desktop, bar none.