> Why not just have an open WiFi network?

I used to do that for a long time. It was great for guests and also for plausible denaiblity if I every got a nastygram from my ISP.

But the liability just got to great and the plausible deniability argument got pretty weak. And also, with so many neighbors with devices that will just auto join open networks, I started seeing strange traffic a lot, most likely from neighbors connecting accidentally.

At the end of the day, making it super easy for guests inside my house without being totally open works out well.