Not really the same. McD's is adding a lottery ticket on top of a regular purchase that sells high volumes at the same price when the lottery isn't running. valve is selling lottery tickets standalone..

Valve is basically doing what Wizards of the Coast has done for decades. I remember there were lawsuits arguing that packs of Pokémon cards should be illegal under gambling laws, especially for children. I can see the point, although I don't think such lawsuits will actually win.