Greetings,
I've searched on the forum, and have seen that async multiplayer was declared "likely to be implemented" by the devs. Main issue to add async play was the cross-platform feature.

This was several years ago.

Is it coming someday?
Would be the best thing that could happen to the game, in my opinion.

Just to develop my thoughts, I'd like to mention this amazing card game, EPIC, by the makers of Star Realms (curently in Alpha, but will be king of card games when it comes out). It features both realtime and async play with 48h turns. This makes a HUGE difference, and would bring SE to a whole new level if implemented.

Right now all TCG are realtime only, and it sucks so much.
SE has that little something that puts it above other TCG such as Hearthstone and co. Please make it shine for good by adding this !

Yours.