My point being that, if they suspect you have weapons, their lives are worth more to them than yours and your family's and they'll not think twice before making that choice before you make yours.

If they enter your house when your family is in, they are prepared for it. You are not.

Remember, it's a violent criminal we are talking about. Were it not a violent criminal, they'd stalk your house and wait for it to be empty. And still it'd be wise for them to expect whoever they find inside to be armed.