They serve different purposes: the "first" outro that's used in the show is just the generic outro at the end of all 38 episodes of the show, whereas the "second" outro is specifically tailor-made for that 2002 OVA. The 2002 OVA is a short little prequel to the show that happens well before she ever receives magic powers (and in my opinion, the outro was by far the most interesting part of it - despite the fact that it has very little to do with what was actually shown in the episode). The first outro, although not particularly interesting or exciting, is really more appropriate for the show as a whole (which is largely upbeat, pleasant, and sincere), while the second outro...I still don't really fully understand exactly what it is they were trying to do. Especially now, because after my previous posts in this thread, I learned that I had previously overlooked that there's actually a 1986 movie (give me a break, this is a fairly obscure show and it can be difficult to find things...), which I just watched a couple of days ago.
The context given in 1986 for 2002's creepy outro and end credits was this: Emi's looking back at and reminiscing of when she could turn into Magical Emi...and at the end of it all, her old broken magical mirror gives a little flash of power, the camera switches to her face, and she smiles. See? It's simple, but now I know everything turned out alright and that she didn't get murdered or kill herself or something, and heck, maybe she can even still do magic...if she wants to. Phew, thank goodness writers and directors back in 1986 knew how to properly convey ideas instead of just being creepy and off-putting for no particularly good reason. After all, it's a magical girl show aimed at, like, 6-10 year old girls, not a David Lynch movie/television series. Why they tried to re-create this 1986 scene in 2002 without any of the surrounding context (and when the original audience would be long gone), I'm not sure, but if nothing else, it helped get me to notice that there was a 1986 version and receive better resolution from it. Not that much better resolution, since this movie was also quite strange in of itself and with the exception of the "looking back" scene partially shown above was neither a prequel nor a sequel to the show but rather took place right square in the middle of it with no apparent purpose, but better. I still don't know whether she ever accomplished becoming a magician like she dreamed of, but even if not, I think it's okay.
All of that is probably quite a bit more boring sounding than some anime director/writer randomly channelling their inner David Lynch for an early magical girl series, but hey, that's life.
There can only be one...