Most "artifacts" are, as stated above, completely useless. You can't trade them, you can't use them, and they generally suck. That's because - at least by default - most artifacts will be made in your Crafts workshop. This leads to various wooden crafts which are useless enough without wasting a strange mood.
Recently, however, I had a gem cutter go into a strange mood. He locked himself in his jeweler's workshop, gathered up a number of gems and came out with a named, perfect gem that found its way into my "Finished Goods" stockpile. I thought I might try searching for its name in the trading screen, but a Rhesus Macaque stole it before I had a chance.
The creator of said gem didn't seem to care. I specifically looked for some kind of bad thought from it, but it never showed up. I'm sure there will be engravings about it later, though.
As for the skill changes, it is unfortunate that possession is ALSO apparently the most common form of Strange Mood. At least it is for me. And last I checked nobody knows if there are any conditions for specific moods (well... except the macabre mood, which requires an unhappy dwarf going into a mood), or what those conditions might be (if they exist).
So usually... I end up with a bunch of legendary wooden or stone crafts and not even a legendary woodcrafter or stonecrafter to show for it.