With the ones we see here, they are all commander-sized, meaning they are aimed to be exciting in the commander format, both in and out of the precon
The trouble was, most decks seemed to run both
Sandworm adding five hasty power plus a bonus round of landfall triggers is overwhelming
The amount of cantripping you do isnt enough to compete with engines like Ichor Wellspring + Deadly Dispute, and you often end up falling behind because while youre cantripping, your opponent is developing their board
This immediate impact usually comes in the form of ETB (enters the battlefield) triggers, and Ephemerate is the best and most efficient way to trigger these effects multiple times
There are also ways to bank a board wipe for later