Brilliant fish-boning and analysis. I was rooting for the ferry choice. Ushuaia is indeed an iconic "to-do-list" selfie destination but IMO, outside of a selfie at a sign...eh? (and that ain't worth squat as I haven't been there and like opinions I also have an asshole..so what). Now if one was gonna go from there to Antarctica upclose you got a maybe yeah. Unlike the iconic selfie at Machu Pichu, another over run & done "to-do-lister", the sight is still something to behold and worth the commonality of its uniqueness (there's a paradoxical statement for ya). Looking forward to your ferrying adventure.