I think Hussar Companies would need something similar, no?
One additional thought: As I was looking at the brick tonight, I remembered that the baseline Anvil Attack Sled is a Zero-Index machine – in other words, that it’s primarily for worlds with no indigenous capacity to produce and maintain Hammer assets.
So that gives us two ends of the spectrum that both would have significant roles for an Attack Company/Battalion: at the low end, Zero Index worlds where there IS no indigenous Hammer around, requiring the use of atmospheric craft to perform recon and strike roles more sophisticated planets would generally use Hammer for; and at the high end, worlds so prosperous and/or well-defended that they can afford to invest in a Low-Index, grav/pressor version of the Attack Sled as a hedge against their Hammer not being around. Worlds in the middle – which have Hammer but not a lot of military resources to spare --would probably not bother investing in dedicated Attack units.
Chris’ notes point out Attack (aka Air Superiority) Battalions are primarily found in the interior. So they would be a way a Forged Lord could get some useful combat power from a fief on a zero-index world, since any infantry raised could have anvil armor, but no grav-lift. Of course, he would have to send the Hammer assets to lift them off and an Attack Battalion would have a much smaller footprint than an infantry battalion.
Air Superiority forces could be useful when you have Space Superiority, but not Space Supremacy. You might not have the Hammer assets to have global coverage. You might need to stop strategic movement anyway.
Air Superiority forces could still be useful in terms of counter-insurgency as well. Maybe they aren’t strictly speaking just for air superiority, but for the strike role as well. Hammer assets might be busy or there could be “politics” or technical issues or lack of intelligence (I’m thinking of no embedded forward observers, for instance) between the Hammer Lord and the Anvil Lord that prevents timely employment of Hammer strikes.