Giclée (French): Pronounced zhee-clay, was an invented term created to identify the process of making fine art prints from a digital source using ink-jet printing. Jack Duganne, a printmaker working in the field, coined the term in 1991 to represent any inkjet-based digital print used as fine art. RE: Wikipedia.
What are they worth? Well, whatever someone is willing to pay; the same as for anything else. Demand always determines value. But if you ask an appraiser, especially this appraiser, if you should buy a giclée, the answer is no.
However there is at least one exception to the rule: If you own a valuable painting that you wish to donate to a museum now in order to benefit from a tax deduction and from the notoriety of making a high profile contribution to your favorite museum, then you might consider having a giclée made of your painting as part of the transaction. The museum will likely jump at the opportunity and you’ll still be able to enjoy the picture over your mantle. It’s a case of having your cake and eating it, too.