Ask HN: What are the very best reasons to develop in python3 over python2?

I just got a new job in a relatively young department inside a Fortune 500. I was delighted to learn that they've been automating their manual processes with python, but surprised that all development has been exclusively python2 since the department's inception 3 years ago.

As for me, I can't imagine python2 is viable due to the impending deadline, but I was unaware of how controversial this was until only recently. I've been happily writing python3 for the past 2 years. I doubt that I've been using the best new features of the language or that I could articulate a compelling argument for python3 without some help.

So, how about it? Can I get some input to essentially create a pitch deck for python3?