Your logic is technically sound, and I'm not faulting you for thinking that way, but for me personally that's an unfortunately regressive way of looking at the world. I'm unsure where the idea that being principled requires being foolish comes from, but I myself would care more about the character of my daughter's husband (and incidentally, the assumed father of my grandchildren). I'm not even sure what one would be trying to optimize for with this line of thinking. Couldn't this same concept lead to: "I'd prefer a man who knows exactly how much to cheat and steal and hurt others, as long as he makes sure the direct cost to him is less than his benefit"?* Is that really a man you'd like to see raising your grandkids?

*Just to clarify, to avoid making this seem like a strawman: I'm creating a deliberately extreme example that to me seems like the logical extension of optimizing for "success" (or minimizing headwinds) at the expense of character (personified in your example by someone who's principled as opposed to a follow-the-herd type person). The purpose of this is to highlight the fact that this is someone you're accepting into your family, and the importance of that becomes particularly clear when you consider that the man he is will in large part shape the men and women you're grandchildren are.