Your unit is invisible on the strategic map. I believe it doesn't work within sensor range of someone's colony, but aside from that + mods and abilities that provide detection, you're invisible. I haven't found a way to really take advantage of it against AI, and I doubt it'll ever be great against them, but it must be fun in PvP. Syndicate mirage makes your whole stack invisible in rough terrain, so I stole a Vanguard mountain sector earlier and vanished into thin air, but his AI galaxy brain probably tells him exactly where I'm going.