I think the question of whether it was used as a weapon or not can be reasoned out (independant of possible accounts or evidence). An oar that has a strong profile taper and point like that would not be as efficient as a broad ended oar would be. Because it doesn't have as much surface area and would let water slip past the tip (even potentially creating some hydro-turbulence). The tip wouldn't be very useful for sticking into crags as it is narrow and wood (it might snap). Also one could just use the handle end to grab bottom or dislodge more efficiently. It's likely not for fishing either, given such implements are often multi-pointed, barbed, or both.
It's obviously been pointed for no increased effectiveness as a paddle (and likely a detriment to it's use as one). So the design feature is a sacrifice in it's functionality to increase it's versatility. There had to be a secondary function that was important enough that they were willing to sacrifice a little of it's ability as an oar. But I don't think we have to leap right to weapon of warfare for having considered all this. While I think using it as a weapon against other warriors when coming ashore (or possibly small scale boat to boat warfare) is a possibility. I'd like to suggest an alternative for a primary function of pointing their oars. That being to fend off potentially aggressive animals such as sharks. Something that small boaters have to do on occasion as shown in this video (one of quite a few videos like this that can be found online):
Man vs. Hammerhead
How much more effective would such an action be if an oar was pointed. Also if meant for this purpose, not being barbed makes more sense as well. Because I doubt one would want their oar to get stuck in a shark. I suspect a small group of warriors could easily defend themselves against even multiple sharks attacking with each of them having one of these. Spending a lot of time on the water this was probably an issue that came up more than a few times. It makes sense to me that they would adapt to the environment defensively in such a manner.