Yes but that means querying the server every 5 minutes or so.. this way the daemon only sends out notifications when there are replies and will send them in real time.. And you only really want it to send one at a time.. Imagine if you hadnt visited the forums in 20 days, opened up the client program and were flooded with thousands of alerts
The daemon is also alot faster than the PHP script... but the daemon is actually written in PHP itself