No, konqueror is still useful as a file manager (some users don't like dolphin for some reason), also as a man pages viewer. Also it shares some code with dolphin (some stuff/features don't work in dolphin if konqueror isn't installed).
I usually use Konqueror as my ftp agent. It works flawlessly. I just recently started to try Dolphin ((Ctrl-l) brings up the URL field) but it just kept kicking me off my sites for some reason.
Marc