Playing a character such as Amiri or Ezren gives you ways to churn through your deck faster, discarding cards quickly to add to your checks or to get to the cards you want. While this makes you far more likely to defeat your enemies and acquire what you need, it comes with a cost: you might kill off your character.
This game is all about trade-offs. Should you press your luck or hold off a bit? Not taking risks will make you lose as often as taking too many risks, but at least your character will be alive.
One of the toughest choices involves shedding cards as you reset your hand. You're allowed to discard any number of cards before you draw up, but that puts you closer to death. There are few things more humiliating than dying because you forgot how many cards you needed to draw at the end of your turn.
When you have too many cards in your hand, that's a different problem. If you can play some cards that can be recharged - even though you might be able to put them to better use if you hold on to them just a little longer- it's still worth playing them. Discarding cards for no gain is more painful.