You do have to discard a card to specialize, but lands can count as the color you need when discarding
Being able to steal your opponents spells is always good, and it opens up the possibility to cast basically anything you steal since you can play them by paying life instead of mana
Grima, Saruman's Footman, Knollspine Dragon, Notion Thief, Shelob, Dread Weaver, Boon of the Wish-Giver, Decree of Pain, Deep Analysis, Lidless Gaze, Fact or Fiction, Relic of Sauron 10 card draw
Each ability can only be chosen once each turn but pair it with the likes of Escape Protocol to blink it and you can activate abilities as much as you're able to
You share them with folks who love surprising opponents with weird old janky cards that are dynamite in the right situation
In the Pokmon Trading Card Game (TCG) , Energy is the economy