Karl Marx qualifies the labor theory of value by saying "socially neccessary" labor time. Meaning Karl Marx believes in utility as something socially determinate and reflected in value.

Land has value, but as the way you're speaking about it seems to presuppose private real property, it "doesnt make sense" with Marx.

Marx uses the word property only to refer to real property. Personal property is called "possessions". So when Marx talks of sharing property, he's speaking of real property.

As the entire basis of the argument for communism is communally owned real property, and class is defined by ownership of real property, land is basically invaluable. It stands at orders of magnitudes above the labour time of the individual. It's basically so valuable that it creates problems when assessing value socially and so must be shared.