And just to add to the PP, it's is a very limited admission that still requires having park admission on top of it. It's an extra cost but:
Low wait times for Fantasyland attractions which takes off any pressure to get FP's for the attractions open during that time. And you get a complimentary breakfast. Pretty easy to hit Space Mountain too when it opens with the rest of the park before going to breakfast (located in Cosmic Rays).
Even if you don't get a ticket for it, EMM does not factor into increased crowds because it is limited admission.
IMO worth it if you have the budget but ultimately not necessary if you opt to attend MK on that day.