Except the OS has no web server, so you have to find and install one, make sure it auto starts, set up port forwarding (which you might not be able to if you're behind CGNAT or your ISP just doesn't let you)... Then you need to explain to your partner that your computer is running 24/7 to host your shared shopping list or whatever, which will definitely cost more in electricity than a 5$/mo VPS, which was already presumed to be unacceptable

"... my wife or kids " you already lost them at "... self host"

GP was suggesting that you would self-host for your wife and kids, not that they would self-host themselves.