Bt is a bacteria. it is not DE which is a natural abrasive which makes microscopic abrasions on the soft bodies causing them to dehydrate to death. Bt is a product they digest causing death. I would use the Bt any day over the DE for results. We use liquid along with a spreader sticker to keep it on the plant. otherwise dew will cause the product to bead up and roll off.
https://www.planetnatural.com/bacillus-thuringiensis/