The appeal of Celtic coins
Like modern art, the best Celtic and other "barbarian" coinage is characterized by the communicating of emotion and the inner vision of the artist rather than a portrayal of the exact representation of nature, an expression of subjective rather than objective reality. By straying from the strict figural or idealized representationalism practiced in the Greek world in favor of highly stylized abstraction, Celtic die cutters brought out the essence of their forms in a strikingly individualistic and evocative manner. Just as Impressionism, Expressionism, and other schools of modern art were a reaction to the prevailing aesthetic standards of the time, so was the numismatic art of these coins.
In the past, the supremacy of Greek representationalism was assumed, and nonrepresentationalism was regarded as degenerately derivative. The publication of Paul Jacobsthal's 1944 book Early Celtic Art did a lot to change this thinking among many academics, but prejudice toward the abstract has persisted, just as some people today uncritically regard the representational work of a Rembrandt as superior to the nonrepresentational work of a Picasso.
But just as not all representative art is evocative or compelling, not all abstract art is either, whether on coins or elsewhere. Hans Rauch described well the differences between stylish imitative Celtic issues and crude ones in his October 1969 article, "The Celts and Their Coinage," which appeared in the Journal of the Society of Ancient Numismatics (SAN). "Frequently the impression is obtained that the artist avoided the reproduction of nature by skillful exaggeration, almost bordering the abstract... culminating in a strange modern and sometimes beautiful effect. It should be stated, however, not all coins... are of artistic merit. Many... were crude, ugly, and truly barbaric."