And yeah, actually the mods can use those files, they just have to be smart enough to point to the right app # to load the correct .gcf in their gameinfo.txt

Also, the episodes are USELESS to the modding community, as they don’t add the new content to the Source SDK Base content. Only things from HL2 and HL2 DM are publicly available for mods. In order to use Episode content, you have to copy the models and textures and use a tool called pakrat to include them in the map file, something that’s against Valve’s ToS.
There’s a number of changes I’d really appreciate see Valve make at this point. Timely development cycles (C’mon, it’s not like you don’t have a big enough team or resources), actually lower prices on Steam than physical sales (Valve games at Walmart are no more expensive, and in some cases cheaper, than Valve games on Steam, and they come with a Case, manual, physical copy of the game, and doesn’t require downloading), and stop practices like gimping products they offer in deals with ATI (They give away HL2: DM and Lost Coast for ATI video card owners, but the free versions aren’t compatible with the Source SDK, which means the owner can’t play mods, and these are games that they ALREADY give away to anyone who buys HL2 (in stores, anyway, you have to pay an extra $5 on Steam) or Episode 1 (which also comes with HL: Source DM). They also need to include ALL the HL2 materials in the Source SDK base. They aren’t exactly losing sales by allowing the stupid TREE models from Episode 2 to be used in a mod for their games. That’s just an absolutely retarded bit of cheepskatery.