If I decided to do this, I would need to operate my LAN like every node was bare on the internet. I've got fileservers with guest access (for, you know... houseguests), web services, my invoicing system, and a whole slew of other personal services. The thought of open wifi on the LAN kinda scares me from a security perspective.
Um. My router has a 'guest network' with a separate SSID. Many free-from-your-ISP routers now do. For a tech news website, there are an astonishing lack of tech solutions in the comments here.
The Wright Bothers weren't the first to fly. They were just the first not to crash.