What do we mean when we say it today?
Way back in the 15th century, people said "he hath eaten me out of house and harbor." Now we might be a little biased, but we think Shakespeare's version is way better. Or maybe it's just easier to say. Either way, it's his version that stuck.
Nowadays, we hear someone say this as a bit of a joke. A mom might say her son has eaten her out of house and home. Or a couch might say the football team eats him out of house and home. But no one is ever (that we've heard of) using this as a lawsuit.
It's all in good fun—an exaggeration meant to poke fun at how much someone is eating.