From the latest Patch Notes
Spectral Allies in Inferno Difficulty
You can now summon Spectral Allies in Dungeons when in Inferno difficulty. Only the best allies would follow you into these lowest depths of hell.
I decided to give that a test and went to the entrance of Mad King’s Breach.
With Challenge Mode selected, Spectral Allies are unavailable…
With Standard Mode selected, Spectral Allies are available…
Clicking on Quick Summon fills the empty party slots with Spectral Allies…
If you then Enter the dungeon, you arrive inside with the Spectral Allies…
As you can see from the Buff list, there’s no daily unbound / bound gem counter buff. This means that the Spectral Allies do not count as players for that, so you can’t use them to run dungeons effectively solo to get your daily 12 unbound gems.