KB: Warriors of the North

Ugh, this is ridiculous. I bought the game on a disc, but Steam forces me to download it from the internet. Question: what's the point of putting it on a disc if you still have to download several GB? And that information isn't even on the disc. Complete nonsense.
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Update: the information seems to be there, but I haven't figured out how to make Steam install it from the disc yet. I'll try again.