First, a word about terminology. In general use the words 'provenience' and 'provenance' are synonymous, merely variant spellings of the same word. In speaking of artefacts however, it has become common to distinguish them as having separate meanings: 'provenience' is commonly taken to refer only to the actual findspot where an artefact was excavated; 'provenance' is much broader and includes the findspot but is more often used to refer to the history of an artefact after it was found, where it was subsequently kept, when it was sold, who owned it, etc. There is no absolute consensus but for the sake of convenience I will use the terms in those senses in this post.
In a post on an antiquities forum, a neophyte collector has mentioned the importance of provenance. A specialist collector of Celtic coinage and other artefacts (and editor of the ACCG Newsletter) has grabbed the chance to pooh-pooh the importance of "provenance" by replying with a few comments which belittle the significance of findspots - but completely misses the point.
A narrow perspective is all too common among many collectors, particularly it seems among those who collect ancient coins. In fact, the neophyte collector was discussing antiquities in general and my comments below address that broad overview.
Judging by posts on blogs and forums, there is a large number of collectors who cannot see the wood for the trees. They are so obsessed with the artefacts themselves (the trees) that they seem to think that the context (the wood) is only important if it provides more information about the artefacts. Their whole world revolves around the objects. Their concentration is understandable but it can easily become an extremely narrow "object-centric" universe.
The Celtic specialist shrugs that proveniences "can tell us only so much as this sort of material often traveled far from its origins". And goes on to say that "If there is no [provenience] and no archaeological context, much of this data can be reconstructed, functionally, from other types of data -- metallurgical analysis, typology, art history etc."
Well yes, I dare say it sometimes can - but that's not the point. The purpose of excavating an archaeological site is not just to provide information about objects found there.
It is not just what the site (provenience) could have told us about the object, it is what the object could have told us about the site.
Indeed, the objects themselves may be of comparatively minor importance. Archaeological excavation lies in carefully deconstructing and examining an ancient site, not just the objects buried in it but the site itself - the whole site, the way it was constructed, the way the finds were distributed, their relationship to the site, to structures, to features, to human remains and to each other, what they contained, and a million other tiny details. The finding of a foreign object (something that "traveled far from its origins") may also be significant. It is by putting all those details together that a meaningful story may emerge.
And when objects are looted, the tragedy is not only that the objects have lost their context (as the Celtic coin collector pointed out, the objects may still have some value anyway), it is that the context has lost its objects. In other words, the site has been robbed of the finds that would have helped to meaningfully interpret it. And in many cases, the site has been totally trashed to retrieve them.
The greed of a looter has destroyed a special opportunity to add to our knowledge of the past. A personal greed has trumped a rare and precious boon for all the rest of us.
That brings us to what the neophyte collector may have really had in mind about the importance of provenance, the record of an object after it was found. A provenance can reassure a collector that the object has not been excavated recently, and that by adding it to their collection they are not supporting a modern looter. A provenance gives the collector an opportunity to avoid contributing to the ongoing wholesale destruction of the archaeological record. There is a great deal of value in that - but only to a thoughtful collector who is genuinely interested in history rather than one who sees only the trees but not the wood.