The fight mechanic was introduced with the [c]Arena[/c] land, which was a promotional giveaway card bundled with the HarperPrism Arena novel
Developer and publisher The Pokmon Company International delayed the official release of the Live app in 2021, and instead announced that a region-specific beta would be released in 2022
In Limited, the 20 power part will basically never happen, but a 6-mana 6/6 with Flying, Haste, and Firebreathing can end the game in a hurry
If youre less fussed by dinosaurs but fancy adding some dragons to your collection, good news
You should also take a look at current prices for each of the major grading companies, their requirements for how many cards need to be submitted at a time, and their turnaround time (how quickly you'll get your card back)
3 mana to copy one of your creatures will be worth it a lot of the time