The problem
Having to click something in the top left, then scroll all the way to the bottom middle, then scroll all the way to the top right, is ergonomically extremely unfriendly. And putting people at risk of RSI.
Since this is a much re-occuring action, it should be as fluid as possible.
Solutions
PC+Mobile: Add a CAST button on top of the card, that appears when you click the card.
You can leave the one in the bottom middle, but I think no one would click it anymore (maybe on phones).
You could even add a CANCEL button under it, so you can click that to cancel the spell.
This would alleviate a lot of total unnecessary mouse movement on PC, and a lot of weird hand holding when playing on a tablet.
PC: You could add hotkeys for clicking a card, for example 1234 or ZXCV acts the same as clicking with your mouse on card 1-4 respectively. Just like how holding L1 and pressing square/triangle/etc…
Talking about console… Could you also add L2 and R2 to act the same as L1 and R1, as they’re not used for anything else? I’d even like L3 and R3 to trigger it… It would make holding the controller more friendlier.
Other improvements
There are actually a lot of GUI improvements you could do to the game, on console as well as on mobile/PC.
And I could make a list of this, if you’d like. But just contact me then, as I don’t wanna waste my time on it if you’re not interested. @Nimhain @Sirrian @Saltypatra