McDonald's already sells beer in Spain, though nothing stronger than that. Either way yeah, there is no reason not to sell beer.
I had never considered this idea until now, but frankly I think it's an injustice (possibly unconstitutional?) that I cannot get a McChicken with a McBeer. I am going to send a sternly-written letter to Joe Biden about this.
McDonalds already allows you to get your McChicken (as well as any other hamburger you want) with a McBeer over here. Feel free to move to Spain any time you want for that