It took me way to long to figure out what the number on the oakheart talisman means -_- The stop effect is small, but making every spell just a little stronger - and moreso the better you're doing - is a nice buff.
Also, buying and upgrading the dot spell is hilarious xD "tap screen, deal 30 damage to all enemies, gain 10 block" feels crazy, but it takes a lot of investment to get it there.
It's definitely fun, and feels like you have to pour a lot into a low node spell to get it to a strong point, so it's not really game-breaking (especially since you won't draw it every turn).
And the oakheart thing makes sense, I was just not thinking so I took a while to figure out the number specifically. Should really have been obvious but I was being dumb lol