In fact, all of these cards are so good that every single one is in my Commander Cube (save for Tower of Fortunes and Loreseeker's Stone) as well as Abes Deck of Happiness and Joy
There are also a lot of good cards that give this effect, such as the mighty Flickerwisp, but only ten can make it into the best flicker cards in MTG
I get that its expensive, but you can generally have it pay dividends right away
The priciest sale we've seen recently is this PSA 10 copy, which sold for a shiny $108,000
To wrap, players put the card inside lots of sleeves and if it would be dealt damage or be destroyed, you remove a sleeve from it
With Commander, there are more opportunities to put more expensive cards into your deck that you might not play with otherwise