Me thinks its great, but a little over excited combination of apples and oranges.
One is a set of historical events which marked the growth and advance of Christianity in Denmark, which, in myths, might give Harold Bluetooth more credit that he deserves. But I think the history would credit the era of Harold as marking the beginning of that large-scale religious conversion process, with or without the myths related to it.
While the artifact represents a single individual, who lived among an unknown group of individuals, of an unknown number and with unknown actual religious sentiments. I don't think that one artifact can alter the history of the general introduction of Christianity to Denmark.
That was basically my reaction to it as well. While the possibility of Christians arriving early in Denmark is interesting and possibly of historic significance, that doesn't automatically displace the significance of later events, at least not without additional information to demonstrate historical continuity between this find and later Danish Christianity. There were cases of Christianity appearing early in a region but not really taking root among the general populace until later. I think maybe the author of the article exaggerated the implications of the find for the sake of making the lead sound more exciting, which seems to happen a lot with archaeology articles: everyone wants to announce the discovery of the "first" something or other.