It showed people trading cards and a new way to play the competitive TCG game
Now, your opponent can do the same, but, if since youre an Emerald deck that can run discard cards, you could bleed them out of resources and potentially leave mediocre plays in their hand, that dont stand a chance against the Character youve developed
There are about a million 2/1s for two mana with some sort of upside that are playable, not just in Standard but in Modern as well, which means Naban, Dean of Iterationwhile restrictive in another way (only working with Wizards)is much easier to build around than Panharmonicon
if any opponent plays around the counterspell mode of Thassas Intervention, you can cast Dig Through Time instead
Whats more, this Leo doesnt have much in the way of costs associated with using this ability