Having a living and breathing village full of people with different needs,wants, and jobs with a lot of QoL improvements that other survival games lack is mostly what made Valheim big. That and a completely different setting than normal with goals and bosses. Everyone in a village needs things to survive, especially surviving raids. Groups need to go out for materials sometimes because it's easier, safer, and fun, that kind of thing.

QoL things like getting all your materials back when you demolish things are pretty big.