Acceleration support gem works on dark effigy? (POE2)

You can use the acceleration support gem in Dark Effigy, it even pops up under recommended gems. But if you hover over acceleration, Dark Effigy has a red cross next in the Supported Skills tooltip. It got me thinking that other "supports projectile skills" gem would work on it, but it seems exclusive to acceleration. Is it a bug?

Well, my understanding is that it doesn't help Dark Effigy, but it will help Vile Effusion, which is what Dark Effigy uses to do damage.