Leaving something to someone you love is a common human motivation, from a father in building a business that he hopes the son continues to run, to a poor woman who punched pennies her whole life only to leave millions to her grandkids.

Answering a "why would" here is a little tough, like conveying to someone "why would you want to make love to a woman" or "why would you bother to have a family" to someone who doesn't get it.

The question is why wouldn't you? I love my kids I want to do maximally for them.