For one thing, at 180 HP , its a real monster, possessing durability on par with other popular in-game tanks like Venusaur ex
The YouTuber paid $5,275,000 for the card, breaking the record for "the most expensive Pokmon card sold in a private auction," according to a tweet from the Guinness World Record account on April 3
Some of this is due to players buying cards on speculation that they will be worth more later, whether because they are rare or they predict they will have a major impact on the games meta
Making a 3/3 flier when you gain three life is no joke, and giving flying to other big-sized ground creatures is an awesome ability
its often cards with the least amount of text that are the strongest
Cards like Avacyn, Angel of Hope and Throne of Eldraine are too much to expect from such a cheap product, but there are many angel staples like Lyra Dawnbringer, Starnheim Aspirant, and Sephara, Sky's Blade that would be reasonable inclusions