Display graphics in Vim? A REPL within Vim? This is precisely the main advantage of Emacs over Vim: Connecting to external processes and doing more than just text editing.
(Don't get me wrong. I am not saying that Vim is bad. But this kind of thing just does not fit its mission statement)
True, REPLs are possible in Vim. Terminals are possible, too. It's not that anything is impossible (it's software, right? So anything is possible), but how easy it is.
Emacs was built for that. Vim was not. Which by the way does not say anything good or bad about either of them. But I would dare say that Vim is most commonly used alongside a terminal, whereas Emacs users tend to run terminals inside Emacs. Hence your normal workflow would be to run iPython alongside Vim or within Emacs.
(Don't get me wrong. I am not saying that Vim is bad. But this kind of thing just does not fit its mission statement)