Lots of statements I agree with above and a few that I don't.
"Use the proper tool for the proper job - unless you are in a survival situation. I am not going to carry a two foot sharpened pry-bar so that I can use my knife like an axe. I am either going to carry a pack axe - or I am going to alter my technique to fit the situation."
I agree, use the proper tool, 100%. I also agree that a good axe is going to be the most efficient wood processing tool considering weight carried, the types and amounts of wood that can be processed, and all the different types of techniques that can be used to do it. However, I do not consider battoning to be a 'survival only' technique. It's an every day technique that has been used long before my time (If battoning isn't a viable technique than what the hell is a froe for?) and again, when done correctly with a quality tool, won't give you any kind of grief.
"It doesn't have to be big to baton. I baton kindling with my Izula 2 all the time." Agreed-it does not have to be thick or long to be a durable battoning tool, just made from good steel designed for the use.
"Carrying an axe is all well and good but if you want to go for a long hike first it will be added weight, so it's nice to be do it all with a good big knife, at least for me! Maybe you can carry more weight than me!

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If I too lived in Ireland, I would much favor a long knife or a machete over an axe. Dealing with alot more brush and alot less hard woody stuff. However, most 'good big knives' weigh as much sheathed as a backpacking axe will, and if you have to carry an extra half pound for the efficiency of an axe, it is 100% justified.
Fortytwo is also correct, that battoning is a practical technique when applied to bushCRAFTing-when making stuff with limited tools, it's a great way to split wood in a controlled manner for making stuff-whether it be a trap, a paddle, a shelter, whatever. It's not only a firemaking technique, need not be limited to as such, need not be limited at all. In fact I think it's alot less abusive than other techniques, both on the tool and on the user. I'd consider whittling down a large amount of wood with a bushcraft knife abusive over a quick battoning split. All that prying side to side in hard media on a slicing edge? No thanks, I'd take a short, fast application of direct force rather than repeated tension and compression on an edge that's finer than hair.