[iffycan]

I won't say never. I think your distinction (GitHub merge vs bill overdue) might strike the right balance, but I'm having trouble sorting out what the principle is that distinguishes those two.

As I've never even paid attention to the sending address of GitHub merge notifications, perhaps the principle is: "If someone notices that your email came from noreply@ then you shouldn't use noreply@"

(And, no, you don't seem critical -- more like thoughtful)