That comes true specially if your desingings are near GUI level mostly.
But for many people specially low level programmers, long document editors, Vi(and Vim) has capablities hardly any other editor has.
One of those capablities is the Black Background!!!
Personally I see only advantages when using console version of
editors/vim under X11, I like it much more than
gvim, because, for example, it is possible to select text with two different types of selection, when using
vim in
xterm or
urxvt, and it's quite handy, because sometimes you need to select text without moving
vim cursor, to do this, just hold shift key and select required text, then you're able to paste it with shift+insert or middle mouse click. To enable
vim mouse support add "set mouse=a" to your
vimrc, so there is really no advantages of using GUI version of vim like
gvim, just disadvantages.
I'm using also black background in
vim , but also I like terminal emulators with transparency support.