I have got to ask a question which has vexed me for some time. Why baton at all? I gather one of the more common reasons is to get at the dry interiors of branches for dry firewood.
Exactly, and it is for this reason that carrying a knife capable of batoning work is a good idea IMO. I have plenty of experience doing this. I keep a Cold Steel Bushman by the fireplace for batoning through small logs or taking corners off of bigger logs when kindling is needed. I try to keep some on hand but somehow I always seem to run out. When out and about, though, there are other things to consider, even more so if in a survival situation. Given a choice I would rather save the energy and do like you said, gathering small dead twigs straight off the trees. Usually dry, but unfortunately maybe not always the case in a survival situation. You may not always be able to find dry kindling this way and batoning may be the only way to get it. Not desirable but good to know my knife can do it if needed. Another possibility is you found some kindling but you need to produce additional kindling. Kindling may be in short supply for some reason. Maybe you used your supply up. Maybe you didn't gather enough. It may be easier and use less energy to baton some of your existing fuel supply rather than leaving camp and hiking around for the purpose of finding some. Or it may be safer to baton than to walk around looking for more kindling, especially if it is after dark.
There is another concern with all this and that is safety. Batoning is not the safest thing in the world to do. Imagine trying to survive AND contend with a bad injury. Same goes for breaking small logs with your feet or knees. We all make compromises and do things we might consider safe to do but we need to think it through. Batoning for me is a last resort but I am still more comfortable carrying equipment I know is up to the task.