"For good" is often used to mean a permanent change, but the context here is using "for good" as in an improvement which isn't necessarily permanent. Either way, that is sloppy writing and the intention should have been made clearer with a slight rephrasing like "for the better".
I read it as permanent as well. Your interpretation makes more sense but is still not accurate because I hardly think a value judgment that cooking at home more is better, for example, is necessarily valid. And I say this as someone who cooked nearly every meal at home not because I needed to but enjoyed it.
