Because the sport cards market existed before pokemon cards, people recognized the value of 1st edition base holos from the start and already graded them 1999 / early 2000s onwards
The best fit for Crush, however, is a token deck like Brudiclad, Telchor Engineer, which can turn your other smaller tokens into 8/8s during combat, or a Sea Monster Tribal deck like Thassa, God of the Sea, where being an Octopus has synergy with cards like Whelming Wave
What attacks does Greavard have
Much like Shattering Spree which I mentioned in the 20 Essential Red Cards the spell is copied, meaning you wont often have the whole lot of your card draw countered
Collectors appreciate it as one of the Pokmon Twilight Masquerade good cards for sentimental and display value, making it a must-have for Eevee and Greninja fans looking to complete their lineup