Like transforming cards, MDFCs only count as their front face anywhere but the battlefield or the stack
It fits perfectly into decks built around flicker loops or reanimation engines, turning every iteration into serious value
They used to be, sure, but in recent days, there have been plenty of changes made that affect either recently introduced mechanics like the companions, but there have also been changes to things that have been around far longer, such as cascade
Mox Amber has a perfectly mutual relationship with multi-colored legends decks
It's just tough to get your mana's worth
Additionally, the Russian version of the Double Masters announcement appears to have revealed a third card, Atraxa, Praetors Voice, though the image was quickly changed before we could verify its authenticity