It was phenomenal when it was initially released, and its just as phenomenal now
Each of these characters can shift the dynamics of battle, especially when paired with other cards in your deck
You can see all the Japanese cards revealed so far in this news story from last night, which features several more that weren't revealed in English today.
The program counted down from Galar, the newest region at the time, all the way back to Kanto, with a new pack roughly every month from February to October
So, in order to maximize that, you'd drop lands and cards from your library first, and then your hand second
So making sure your opponents summon is wasted by using Bottomless Trap Hole, was a good way of pinning your opponent down