“That odd man Buttons may be made fun of for his weird, hobby and obsession. But one of his magic buttons could save your life one day”.
When was the last time a character caught a cold or flu? Real people get them every now and again even with solid heating and dry interiors. Your characters are out in the cold and wet, and even inside is not always dry and warm. Imagine having to stop your dungeon crawl, sitting in a tight defensive position, while you all are feverish.