Picking a .308 in a long action over a .30-06 doesn't make sense to me either. The big advantage of the .308 over the .30-06 is short action. I don’t really think it’s that much of an advantage, so I guess that means it isn’t much of a disadvantage to have a LA in whatever caliber. I can see someone picking a .308 long action for a couple of reasons. A. They don’t know that it’s a long action/don’t even know what action length is. This is probably most of them that pick a .308 in a long action. B. Really like .308/load for it/have lots of guns for it and decide they really want that Tikka but don’t want to add a new caliber.
