Mobile - While it is an overall plus that you can play on mobile devices, if I let my screen lock or if I tab out, the game will no longer recognize my account and makes me re-login via the QR code.
This is what I do to avoid that: I send an e-mail to myself with the link, and I click on the link in the e-mail on my phone. When needed, I click again on the link.
Big brained move. I didn't even think about that.