The really high prices paid by top level collectors are only for PSA 10 cards, and a PSA 10 is very often worth more than twice as much as the exact same card at PSA grade 8 or 9
It's really good in situations where youre chump blocking
For -2, you can bring mill through your deck to bring out powerful creatures
I dont know Japanese, Im just plugging each paragraph (or group of short paragraphs) into Google Translate and then pasting it into a Google Document
We can imagine that, in the future, a card with the Battle type that its own controller needs to protect from to gain a recurring benefit, but with a severe punishment if it leaves play, may arise
Some abilities allow paying a mana cost in a different way, such as Convoke or Delve