Low cost cards can be played quickly in the early stages before the opponent is in a position to defend, whilst high cost cards can be played later in the game to dramatic effect
It enhances the overall gaming experience by incorporating a personal element and stimulating out-of-the-box concepts
Now, it simply lets you pay two mana to move the card from the Command zone to your hand, where it can be cast like a normal creature
I think, like, what Satoshi Tajiri, the creator of Pokmon, when he was catching bugs, I imagine that's what he wanted, is for people to kind of get together, share these experiences, have the same fun that he was having and be able to indulge in catching little critters where he was catching bugs
The smart thing to do when looking to begin collecting is to double-check the lineup of cards for that certain series and see which gold or other rare cards are offered in it