Well, you could compare notes with the Nara at least.
A Kurama spy or assassin specializing in shadows could do some damage listening or killing unexpectedly from a extended shadow, but unlike a Nara, the Kurama Alter would probably make it real obvious the shadow is supernatural and the distance factor isn't even that valuable considering clans like the Inuzuka exist in the same village that can hear a fly fart at 300 meters or the Hyuuga that can read lips from underground a kilometer away. Besides, other shinobi will look out for shadow manipulation from the leaf.
Unless you can replicate the theoretical Nara trick of 'touching every shadow' you have range to at night, that'd be very very dangerous, like a major reality warping 'always surrounded by a army' at night. Well, depending on mental strain, but that's what shadow clone is for.
Actually a Kurama that can create a large false night that's hard to dispel and a high level Nara + literally any random shinobi could be very effective in both day and night. But since most Nara have no endurance to speak of (supposedly, maybe a lie), i bet Nara that can do large scale kagemane and hold multiple shinobi are thin on the ground.