This is the 10th Anniversary sale. Why buy this instead of the GoG version? Cheaper + achievements + trading cards makes a tempting alternative to the DRM free GoG variant.
Also on Steam, Bound by Flame is $8 US, a historical low. It has that Denovo extra DRM which apparently hasn't been circumvented for this title. Dragon Age Inquistion uses that protection as well. Bound by Flame http://store.steampowered.com/app/243930