I mean, “need” is a pretty strong word. No one needs a MacBook Pro, you can do everything on a Raspberry Pi just slower (exaggerating but you get the point). Personally, having reliable internet has been a significant increase in quality of life but admittedly, mesh routers are getting closer and closer. The biggest draw are VLANs. When even the FBI recommends separate networks, it shows how prevalent these issues are. I know a bunch of people that got affected by cryptolocker. While having good practice is probably what helps me a lot, a hardened network helps tremendously.