Use on extinction to gather element dust and crystal from lamp posts and tables. If you have a crab (argy or quetz also work) you can quickly solo run ele dust (I got about 15k in an hour on 1x). You just have to put the doedicurus on wander and carry him near a lamp with your other tame. Make sure you empty him every 2-3 swings or he will overencumber on crystal and won't swing automatically any more. Of course he also cannot be on follow or he won't auto swing either.
On PS4 I tried to test it's obsidian gathering since it is "Rank 1", well all it was gathering was stone. So I went to another saying maybe something was wrong, NOPE it does not gather obsidian. Just use an Anklyo for that.