I had raised this one previously on the old forum, but lets do it again here ;D
By a quick count there are only 7 armies that can have No Camp as an option - Turgesh, Uyghur Khanates, Tribal Mongolian, Pre-Conquest Mongol, Mongol Conquest, Chagatai Khanate and later Nomadic Mongol; so 5 Mongols and 2 others. I'd note as an aside that Mongol Conquest is the only one of those without the requirement that No Camp can only be chosen if there are no infantry used.
I don't believe that the Mongols + 2 others were the only ones who operated in a way that is represented by the No Camp option. I would suggest that it was applicable to any "true steppe nomad" types. On the old forum I posted something about Seljuqs operating this way - many days away from where they "camped" so as not to be hindered by a baggage train.
I also wondered about some other cavalry armies having it as an option - IIRC I posted a case of an Ayyubid army fighting a very significant distance away from their camp such that it had no impact on the battle. Such cases are less clear cut though IMO than the steppe types above.
Obviously having no camp can be dead useful for a shooty mounted army as it removes a target that the opponent can try and get to, however, if we believe that we have the points correct it should not unbalance the game. I'd also note, having been on the receiving end, that a determined/focused and/or skilled opponent can still pin a cavalry army against the table edge regardless.
As someone who plays them occasionally - Parthian springs to mind.
When everyone's on a horse, you'd think we could put the camp like 5-10 miles to the rear, so as to not lose the game on account of said camp!
Timurid armies