Nice find of a cheaper price! It's kinda confusing, though, how that store is being able to sell it for such low price compared to Steam... Are they intentionally selling it for little (or none) profit simply in hopes of attracting more potential future customers?
My subscription allows you people to exist on this site and makes me a better human being than you'll ever be
I would guess that this is being sold at cost or perhaps with a slight loss to get you interested in the platform. The problem is that it's installed on Steam, so you don't really have any attachment to the platform.