Like most Magic: The Gathering cards, the value of Court of Ardenvale depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Wilds of Eldraine Commander)
For example, suppose you control Edgar, King of Figaro and Ral Zarek and you activate Ral Zarek's last ability ("7: Flip five coins
Card bans affect MTG Arena just as they do paper Magic - so the above MTG banlists apply to Arena too
One of the most famous of these cards, Faithless Looting, reads: Draw two cards, then discard two cards. At 1 Red mana, Faithless Looting remains a staple in quite a lot of decks, and is banned in Modern literally because it fueled so many Graveyard style decks
While its a card that doesnt jump off the page as overly powerful, the Cauldron has already had a huge impact across formats, and carries a price to match