I'm told that they aren't weapons (so they can't be sheathed), their damage isn't impacted by bard songs, nor is it increased by DMP.
None of these things are mentioned in the help files, but if true, they reduce the value of the items considerably; if it's not possible to use offensive DMP from bard songs / darkbrew / etc. then it leaves these abilities rather behind their counterparts, and leaves one with a much more muddled and confusing determination on whether or not to use one.
For example, if it's fatally weak to Divinus damage, but terribly weak to fire damage, should you use a fire attack that can have DMP adjust it versus your very expensive artifact? It's currently impossible to tell as there is no indication as to the percentage of weakness aside from the descriptor itself (which covers a wide range of percents).
I'd appreciate clarification on these from whomever knows, as I'd rather not splurge just to find out that things don't work the way one would reasonably expect them to. Thanks!