Besciamella is a sauce, you don’t eat it as is. You use it for preparations like lasagne or manicotti or cannelloni. In America, besciamella has been substituted with mozzarella and ricotta which is the way Italian-American lasagne is defined (with a lot of cheese). The Italian lasagne doesn’t have that much cheese, only some parmesan to add saltiness and flavor. The fluffiness and richness is from besciamella, which is easy to make.