In minecraft's code and files, boat with chests have their own chest texture and model. Its purpose for replacing the original chest model is unknown for me, but it may be a leftover from a developer's testing that somehow made it into the release. Minecarts with Chests and Boats with Chests are not meant to have animations nor sounds (as said in MC-173400 and MC-249383's resolution), so it seems a bit incoherent to have a model with 'animable' pieces.

Also its texture mapping is inconsistent with other chests on minecraft, wich may confuse people that make resource packs.

This is not a duplicate of MC-249378 since this bug is about the model and its "extra" unnecessary code on the chest boat model, not about the texture itself not having a christmas variation. Thought all this could be invalid, I'm not completely sure if it really is, so the confirmation statuts would depend.