It's not even that the setting or scenario is especially appealing, not like, incel transmigrates into man who has harem pheromones or lifelong weakling becomes the demon queen or etc, MC is thrilled because five minutes ago they were dead and for several years before that they were terminally ill and now they're not either of those things.
Local villagers are like, please help us the dark magic blight is killing our crops and poisoning our wells, and MC is just like, yeah sure I'll help! I love wells! The sky is beautiful and doing stuff is amazing! Come, take my hand and look at this rainbow, and also this spider web, and also these really neat shadows, oh wait that's the ever-encroaching evil lol nvm although it is pretty cool looking. Yeah okay I'll carry your sacred light talisman into the catacombs to help stave off the Dark One's awakening. My calendar's clear so why not? Let's bring along a packed lunch and make it a picnic! If the Dark One does awaken anyway maybe he likes little finger sandwiches. Who doesn't, right?