For anyone that didn't understand Connie's joke in the beginning of this episode. He said "Eren no ie ga", which means "Eren's house" and sounds like "Eren Yeager" at the same time, but it was translated to "Eren's house is eavesdropping" instead.
Obviously can't really translate that joke to english.
There is so much depth in his words, that it reflects on one of the noblest ways to live. We just live our lives without knowing the purpose, but that doesn't mean they are meaningless. We give our lives the meaning we want and strive for a better future for the next generations, so that they can give that meaning value.
It was a brilliant strategy the issue is more of a moral one. Their situation is a lot worse than it seems. It is impossible for anyone other than Eren and maybe Mikasa and Levi to escape. Erwin knew this and made a plan that has a slim but better than 0% chance of working.