Ludwig von Mises describes homo economicus as fictitious and hypothetical. It pictures a being driven exclusively by economic motives, i.e. solely by the intention of making the greatest possible material or monetary profit. The homo economicus image of classical economics is certainly not an ideal type, but it helped classical economists explain the formation of market prices.
However, the classical economists failed to provide a satisfactory theory of value that traced the phenomena of market exchange and production to their ultimate source, the behavior of consumers.
Source: Human Action, 3rd revised edition 62-64.