I think there are far more nameservers allowing AXFR than you think. Write a little app that attempts a zone transfer for the top 1000 of the Alexa list (http://s3.amazonaws.com/alexa-static/top-1m.csv.zip) and see for yourself. (Note to anyone reading: Please don't try this before you've checked if it's legal in your state/country or not.)

Could you explain how you would learn about wide-open-dev-machine as simply as by using AXFR in your scenario (you aren't on the network, so no *casting).

Edit: "so what possible reason could there be for enabling it?" is eerily similar to my message :)