I second the recommendation. I even bought it twice (once on ipad and once on android.)
I never played the cardboard version (weight 4+)
Crossplatform play is implemented but I have not tested (various timers for once a day play, or live play with short timers)
I’ve been staying up till 3:45 every day playing this in bed. The app is good interface: you can undo things, you can minimize screen popups to see the situation… (think of all that Tom Chick article complaining how PC strat games fail at this).
Best part of android version is it runs acceptably on an emulator so I can use a big laptop!
One not-so-obvious tip:
A two player game is very different from a three, or a four player game. The two player is duel mode where you really want to hurt that one opponent. A three player suffers from a tripod problem so you carefully balance who you hurt. A four player you focus on expanding your own shit and don’t have to pay laser focus on your opponents ( i mean, you could but it’s not worth doing against AI imo).