It does a lot of things, though many are somewhat subtle, like screen locking timeout and stuff with networking and a bunch of utility programs and so on. I like to start off Xfce Debian and plaster i3wm over it, it's the best 'power user' setup I've come across.
I wouldn't hesitate to put a 'regular' computer user in front of Xfce, it strikes a nice combination of simple and discoverable with very few annoyances. It's also where I go when I want to use some many-windowed application that doesn't fit into tiling.
While it may seem overblown, it's absolutely RIDICULOUS how fast it flies on contemporary systems, and even older ones.
One can also omit most of their other apps, with the exception of KWIN, drawing the desktop and its window decorations, and konqueror, the filemanager, and the things managing the menu(bar(s)), applauncher.
Using modern apps for the rest, like anywhere else.
And have them styled, themed however you like. With a few mouseclicks.
