LP and oil do different things. Oil hydrates and nourishes your boots, keeps them healthy. LP protects them with wax, and adds some oil to them as well (LPs whole thing is that it slowly releases neatsfoot into the leather over time). I would say that the LP is more useful than the oil, but it does depend on how you wear them. You don't *need* LP, but I prefer to never have to worry about the conditions I wear my boots in.
I personally put LP or beeswax on all of my Horween shoes. I feel that they keep a better appearance over time, the patina still looks great, but I never have to worry about "oh shit, I spilled coffee on my shoe, wat do?" That said, I'm also not the kind of guy who goes around with a toothbrush to keep my sneakers white.