GTalk on the iPhone

Google announced browser-based Google Talk for the Apple iPhone and iPod Touch today. Although it‘s not in the form of an iPhone application, using the iPhone scripting libraries Google created a similiar environment on your iPhone than what you used to on your desktop.  In your iPhone browser, just go to, sign in and start chatting. Typing on your iPhone screen is quite tedious hopefully the screen keyboard is better with the iPhone 3G.
Since this is a web app, Google Talk for the iPhone only works when it is the active window in Mobile Safari. Close the web broswer, or switch to a different window and you‘ll show up as unavailable in Google Talk.
With such a basic service why did it take Google Labs so long to release a iPhone enabled GTalk, perhaps they are saving the best for their own Android?