What's the point of Yii's AssetManager?

[GN8]

I can't find much information about Yii's AssetManager for the management of JS and CSS files. My question here is what is the point of using the AssetManager? I'm not sure what value it adds to my development process, in fact, it seems like it complicates my code... every time I change my scripts or css code, I have to go in and delete my assets folder to make sure I have the latest versions.Seems it is much simpler to just put all Javascript files under /webroot/js/ and just use the tags to load the files instead of going through the trouble of AssetManager. Plus, Yii's registerCoreScript function always places script tags inside the header tag, instead of placing them at the bottom of the code, near the closing body tag, as recommended by YSlow.I think there must be a gap in my understanding of Yii's AssetManager. Anybody have any ideas why using the AssetManager is better than hard-coding the script tags inside the PHP code? I'm a bit confused...Thanks!