Don't forget that True20 has a failsafe for regaining Conviction...
Even if you never bother playing to your Virtues or Vices... Even if the Narrator never gives you a cookie when you do play to your Virtues or Vices...
You always gain one Conviction back every day in-game, regardless of whatever else you do with your character.
I like the way Conviction works. On one hand, it's an "Action Point" system the recovers at its own at speed fast enough so that the players aren't compelled to hoard them, but not so fast that they are meaningless. On the other hand, it also provides a good way to occasionally reward players for playing their character in an appropriate manner, or for coming up with neat idea in-game.
So, to use the analogy above, its more like giving a child a standard weekly allowance, and then offering bonus allowance money in addition to that for doing extra chores.