We learn from experience, it's a cliché, but it's true. It's about Splinterlands, so I'm in a position to play Splinterlands, battle with opponents that have been determined by the game algorithm, and also with the rulesets that have been given.
One of the rulesets is Poison, so every round, each monster will lose 2 lives due to poison.
My opponent uses a Fire deck, and what makes me curious is why the monsters on the front line are not affected by poison, this is still a mystery to me until I finally found an article that discusses Cleanse ability by 
At level 3, this monster gets 3 speed with 4 health along with the Cleanse ability. The cleanse ability will remove any negative status from your front card like - poison, slow, etc.
I don't use cards that don't have attack abilities very often, but it turns out that the abilities they have really have a very huge effect, in addition to having a small amount of mana, of course, it will be very helpful for us to use them in battle.
This is a short post, I am just about to share new experiences that I faced and I finally found the answer after reading the related post.
The point is, every card has their own abilities and have its own benefits, nothing is wasted. What we need to know is learn the capabilities of a card inside and out, because lack of information can sometimes lead to defeat and frustration, so let's learn together from our own experiences and of others.
If you want to try Splinterlands, you can use my referral link. Game on!!!.