Auxiliary Support Detachments

Has anyone been making use of these in DE lists? I recently realized that they may be fair useful for us. If you're taking say a kabalite battalion and a coven spearhead and you want a unit of reavers, it's a nice way to add in a unit without needing to worry about troop/hq taxes. Unsure though if the auxiliary detachment gets an obsession though, be nice if it does. Either way seems like it could be useful in some cases.

The Auxiliary Detachment would get an Obsession.

I think there are definitely cases where it's worth paying 1CP to include a unit you couldn't otherwise include, a Farseer springs to mine as worth it if you don't want to spend the points on more Craftworld options.

I think the only thing that makes this choice a little frustrating is the current limitation to 3 detachments.

I've used it with my Harlequins to bring in the Eldrad model that came with the Death Masque box set. It definitely has it's uses. bringing in a ravager for Covens is also not a bad idea.

I have been using some auxiliary detachments, primarily just a farseer on bike, or a Hemlock wraithfighter. However I only tend to do this if I already have a bunch of command points (double battalion), otherwise I think giving up command points for single units is generally too much. Although I do make an exception for the aforementioned doom seer most times simply because doom is just wayy too helpful for our army as a whole

I agree, a farseer or Eldrad is an easy choice if you want that; but the auxilliary can not make use of the stratagems of its faction.

I've brought the Yncarne. The auxiliary appears to bypass the restrictions on a Ynnari army and the loss of Stratagems is largely irrelevant. I don't think it would be competitive, but it is fun to bring the beat stick periodically.