For dueling you can use whatever you want to as long as your opponent agrees. So that means DN, YGOPro and DevPro to. And you can duel on whatever server you want to :D
People tend to use DN cause it's much simpler to access than Devpro/YGOpro by the means of you don't have to download DN on your computer which makes it much simpler to use. Overall everything else what Lokos said.