For easier distribution - it's just a single file to copy. We have a web app that has more than 34000 files; copying those over the network would take a long time.
It's also more orderly to initialize. The servlet engine knwos what to do with a war file, while if you copy individual files, it might try to start initializing the web app as soon as it sees the web.xml file, which may be too soon (because some files are still missing).
Ping & DNS - updated with new look and Ping home screen widget