Chaitén is not pretty in the polished sense. It is a small Patagonian port on the Carretera Austral, rebuilt after the 2008 eruption of Volcán Chaitén sent ash and mud through town. That disaster is still part of the place: a few scarred buildings remain, and the volcano is close enough to feel less like scenery than a neighbour.
The reason to stop is the wild country around it. Pumalín Douglas Tompkins National Park begins just north and east of town, with rainforest, waterfalls, ancient alerce trees, and steep trails into volcanic country. Chaitén also has ferries to Chiloé and Puerto Montt, so many travellers meet it as a transport hinge and then realise it deserves an extra day.
Come prepared for rain, rough timing, and limited services. If the weather opens, the climb to the volcano crater or the long approach toward the Michinmahuida glacier is exactly the kind of spare day Patagonia rewards.