This is a fine technical accomplishment, but at 68# and 1000hrs printing we don't have much to worry about.
I also wouldn't want to rest my body on the inside bottom.

ABS is really fairly strong, but it is still unreinforced plastic.

Think about what it "should" cost at 1000hrs. $5-10K without profit?

I don't think we need to feel threatened.

Like Jeff said it has a lot of promise for protoyping. 3D printing is basically a one-off exercise at present and likely to remain so for some time as far as mass production of identical items like plastic kayaks is concerned. In production it's main attraction would appear to be for customizing boats for those with the desire and money for it.

Compared to prototyping in wood or fiberglass, it has the advantage that the material can be closer to that used in a production facility so might give a moe accurate evaluation of a new design than a wood proto. Comapred to rotomolding it is likely that the design would not have to be so compromised to accommodate the limitations of the process.

As far as home-built wood boats are concerned, no threat at all! Most of us would continue doing what we do even if there were easier, better, cheaper and quicker ways to build a boat just because we like working with wood and love the results we get, and as a boat material there is still nothing better. Nothing will ever gather an admiring crowd on the beach like a well-made, well-finished wood boat. ABS? Stop kidding me . . .