I look back at this and do laugh to myself quite a lot. My girlfriend was super keen to see the penguins and we had some spare time in Patagonia before one of our big hikes, so decided to head from Puerto Natales to Punta Arenas and arrange one of the day trips to see the King Penguins in Porvenir. Yes the penguins are cute, yes the Fernando Cordero Rusque Museum in Porvenir is worth a quick look, and yes getting a couple of ferries can give a chance to look at the landscape from the water. Unfortunately though, my recommendation would be don’t do it mainly because:
Reason#1 You’ll be spending the full day travelling from Punta Arenas to Porvenir for roughly an hour looking at the penguins.
Reason #2 The penguins, cute as they are, are roughly 80m (250 feet) away so you have to look at them through the telescopes provided / just squint a lot.
Reasons #3 Both the penguin colony at Useless Bay, the museum and the ferry stops can feel quite crowded, which is a bit of a sharp change after having vast areas to yourself in the areas around.
Reason #4 The scenery is quite nice, but nothing compared to the sights to the north in Patagonia around Torres del Paine (see 3 very civilised days in Torres del Paine National Park for some inspiration), nor to the south around Ushuaia in the remainder of the Tierra del Fuego (see A trip to the end of the earth, 4 days in the Tierra del Fuego for further tips).
Reason #5 Even with the penguins, you could get far closer and see more, albeit smaller, penguins in the Beagle Channel next to Ushuaia.
Reason #6 Punta Arenas felt far more industrial and quite frankly less to do that the more quaint Puerto Natales or the more bustling Ushuaia.
Reason #7 The trip from Puerto Natales to Punta Arenas and back takes up the best part of a day either side of the day trip to see the penguins. But, that is our own silly fault for planning that.
Not a fan!