First, remember that sand is a kind of soil that has a much greater proportion of large, coarse particles (sands) than small particles (silts and clays).
Sands generally have less fertility than soils with more silt and clay, and so require more fertilizers to produce healthy crops. Sands also hold less water for plants than do silts and clays.
But clays can have their own problems, as sometimes they hold too much water, or don’t let water drain, so there is not enough air in the root zone, and plant roots drown. There are very few silt soils that exist in the world.
Almost all soils are a mixture of sands, silts, and clays, and the best soils are mixtures called loams, which have about equal parts of sand and silt, and a little less clay.
Natural soils always have organic matter in them, the stuff left when dead plant and animal parts and poop are mostly decomposed.
People have learned to help plants grow on all kinds of soils, but I must confess that I have difficulty growing plants in sand, as I have been trying to do since I moved to Albuquerque, especially when combined with the salty water I have available for watering my garden.
So sand is soil, but in some soils, especially loams, it is easier to provide what is necessary to make plants grow well.