That gives M Rayquaza-EX 105/108 both artwork appeal and nostalgia value, which is why it has remained one of the standout Mega cards for collectors long after the XY era ended
When you flip it faceup is when you pay the megamorph or morph cost, and thus the time when your opponent sees what card it is
These are the regular copies Im talking about, nothing special
This is one of the more common questions, and the answer is delightfully consistent with how most other Magic mechanics work
That could lead to some fun combos, but again, it depends on which cards he can combo with
You can also get extra utility from lands like Boseiju, Who Endures or Otawara, Soaring City, which act as interaction pieces instead of just mana sources