For just one mana, you can sacrifice Zack to make another creature indestructible AND give it his counters AND move any equipment attached to him over to that creature
One of each without a bundle is $420, which is a 5% saving
Example 2: Kenrith, the Returned King This is an example of a commander that has a different color and color identity
You could make a fair argument for an army of 2/2 flying tokens being better than 3/3s given how much harder they are to block, but you more than make up for any power lost in the tokens when you add another color
No silver-bordered stuff or commanders youd have to barter for, like Ormendahl, Profane Prince or Heroes of the Realm cards
After the triggered ability resolves during your end step, however, you may tap him for , even if he entered the battlefield this turn