so that servers can host the map .bz2 and have the files compressed for downloading, basically pakrating gives all your custom content free compression downloading. Plus it's cleaner and easier to do the resource file and co, if you have like 150 custom files you just click auto on pakrat so it populates with all the stuff in your map not from a gcf and delete all the common stuff out(like known installer textures and tool textures). Easy as hell.
You do know that both main servers have scripts to bz2 every single texture file in the space of like 3 seconds right?
But it is a pain when you have to use this because the vmf you were told to update looks like this. So that I have to use this. (I'm just ranting on source atm).
I did not actually, aint that handy! I'll still prolly use pakrat though for the simplicity of the 'Auto' button.
Releasing textures and models along with the map instead of burying them in the BSP also means taking responsibility for them, which isn't something you can always do if you're still planning on changing them or using models which you shouldn't be distributing around.