Joe Daggert is the complete opposite of Luisa Ellis. He is a risk taker which is evident by his choice to establish himself financially. The canary going crazy and him knocking over her work basket symbolize the chaos he represents.
Luisa Ellis did not want to marry Joe Daggert. She may have at one time, but that was long ago. She is independent and set in her ways. She did not welcome the chaos this union would bring. It would be disruptive to her routine and the lifestyle she has become accustomed to. However, as she is a rule follower, she made a commitment and was willing to stick to it. Over hearing that conversation provided her with the window of opportunity she needed. She was able to see the Joe felt the same and they were both willing to move ahead out of obligation.
Is Louisa “noble” in giving up Joe? I don’t think so. While she gave up Joe, it was already established he could not have what he truly wanted, Lily Dyer. She gave up Joe as it was the right thing to do for the both of them.