This is kind of necessary. You could open a store just selling Steam keys. You get Steam’s software distribution, installed user base, networking for free and pay nothing to them. Steam is selling all of those services for a 30% cut. Since your overhead is $0, you can take just a 1% fee and still turn a profit because Valve is covering 99% of your costs.

Steam could disable keys or start charging fees for them. As long as they’re being this ridiculously generous and permitting publishers to have them for free, some limitation makes sense.

I’m dubious, though. There must be a provision for promotional pricing. I’ve definitely bought keys for less than Steam prices.